What are cold and cough medicines?

Cold and cough medicines can help relieve symptoms of a common cold. The symptoms of a cold can include a sore throat, stuffy or runny nose, sneezing, and coughing.

You don't usually need to treat a cold or the cough that it causes. You can't cure a cold, and antibiotics won't help you get better. But sometimes the symptoms can keep you awake or cause a lot of discomfort. In that case, cold and cough medicines can sometimes be helpful.

What are the different types of cold and cough medicines?

There are lots of different cold and cough medicines, and they do different things:

• Nasal decongestants - unclog a stuffy nose
• Cough suppressants - quiet a cough
• Expectorants - loosen mucus in your lungs so you can cough it up
• Antihistamines - stop runny noses and sneezing
• Pain relievers - ease fever, headaches, and minor aches and pains

What do I need to know about taking cold and cough medicines?

Before taking these medicines, read the labels and follow the instructions carefully. Many cold and cough medicines contain the same active ingredients. For example, some of them include pain relievers. If you are taking these medicines and are also taking a separate pain reliever, you could be getting a dangerous amount of the pain reliever.

Do not give cold or cough medicines to children under two, and don't give aspirin to children.

What else can I do to feel better for a cold or cough?

If you decide that you don't want to take cold and cough medicines, there are other ways to feel better:

• Drink lots of fluids
• Get plenty of rest
• Use a cool mist humidifier
• Use saline nose drops or sprays
• Use nasal suctioning with a bulb syringe, which can be very helpful in children under a year old

Sore throat and runny nose are usually the first signs of a cold, followed by coughing and sneezing. Most people recover in about 7-10 days. You can help reduce your risk of getting a cold: wash your hands often, avoid close contact with sick people, and don’t touch your face with unwashed hands.

Common colds are the main reason that children miss school and adults miss work. Each year in the United States, there are millions of cases of the common cold. Adults have an average of 2-3 colds per year, and children have even more.

Most people get colds in the winter and spring, but it is possible to get a cold any time of the year. Symptoms usually include:

• sore throat
• runny nose
• coughing
• sneezing
• headaches
• body aches

Most people recover within about 7-10 days. However, people with weakened immune systems, asthma, or respiratory conditions may develop serious illness, such as bronchitis or pneumonia.

How to Protect Yourself

Viruses that cause colds can spread from infected people to others through the air and close personal contact. You can also get infected through contact with stool (poop) or respiratory secretions from an infected person. This can happen when you shake hands with someone who has a cold, or touch a surface, like a doorknob, that has respiratory viruses on it, then touch your eyes, mouth, or nose.

You can help reduce your risk of getting a cold:

• Wash your hands often with soap and water. Wash them for 20 seconds, and help young children do the same. If soap and water are not available, use an alcohol-based hand sanitizer. Viruses that cause colds can live on your hands, and regular handwashing can help protect you from getting sick.
• Avoid touching your eyes, nose, and mouth with unwashed hands. Viruses that cause colds can enter your body this way and make you sick.
• Stay away from people who are sick. Sick people can spread viruses that cause the common cold through close contact with others.

How to Protect Others

If you have a cold, you should follow these tips to help prevent spreading it to other people:

• Stay at home while you are sick and keep children out of school or daycare while they are sick.
• Avoid close contact with others, such as hugging, kissing, or shaking hands.
• Move away from people before coughing or sneezing.
• Cough and sneeze into a tissue then throw it away, or cough and sneeze into your upper shirt sleeve, completely covering your mouth and nose.
• Wash your hands after coughing, sneezing, or blowing your nose.
• Disinfect frequently touched surfaces and objects, such as toys, doorknobs, and mobile devices.

There is no vaccine to protect you against the common cold.

How to Feel Better

There is no cure for a cold. To feel better, you should get lots of rest and drink plenty of fluids. Over-the-counter medicines may help ease symptoms but will not make your cold go away any faster. Always read the label and use medications as directed. Talk to your doctor before giving your child nonprescription cold medicines, since some medicines contain ingredients that are not recommended for children. Learn more about symptom relief of upper respiratory infections, including colds.

Antibiotics will not help you recover from a cold caused by a respiratory virus. They do not work against viruses, and they may make it harder for your body to fight future bacterial infections if you take them unnecessarily. Learn more about when antibiotics work.

When to See a Doctor

You should call your doctor if you or your child has one or more of these conditions:

• symptoms that last more than 10 days
• symptoms that are severe or unusual
• if your child is younger than 3 months of age and has a fever or is lethargic

You should also call your doctor right away if you are at high risk for serious flu complications and get flu symptoms such as fever, chills, and muscle or body aches. People at high risk for flu complications include young children (younger than 5 years old), adults 65 years and older, pregnant women, and people with certain medical conditions such as asthma, diabetes, and heart disease.
Your doctor can determine if you or your child has a cold or the flu and can recommend treatment to help with symptoms.

Causes of the Common Cold

Many different respiratory viruses can cause the common cold, but rhinoviruses are the most common. Rhinoviruses can also trigger asthma attacks and have been linked to sinus and ear infections. Other viruses that can cause colds include respiratory syncytial virus, human parainfluenza viruses, adenovirus, common human coronaviruses, and human metapneumovirus.

Know the Difference between Common Cold and Flu

The flu, which is caused by influenza viruses, also spreads and causes illness around the same time as the common cold. Because these two illnesses have similar symptoms, it can be difficult (or even impossible) to tell the difference between them based on symptoms alone. In general, flu symptoms are worse than the common cold and can include fever or feeling feverish/chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches and fatigue (tiredness). Flu can also have very serious complications. CDC recommends a yearly flu vaccination as the first and best way to prevent the flu. If you get the flu, antiviral drugs may be a treatment option.

You have flu symptoms, so you've been getting some relief for the past two days by taking a cough and flu medicine every few hours. Late in the day, you have a headache and you think about grabbing a couple of acetaminophen tablets to treat the pain.

Stop right there.

What you may not realize is that more than 600 medications, both prescription and over-the-counter (OTC), contain the active ingredient acetaminophen to help relieve pain and reduce fever. Taken carefully and correctly, these medicines can be safe and effective. But taking too much acetaminophen can lead to severe liver damage.

Acetaminophen is a common medication for relieving mild to moderate pain from headaches, muscle aches, menstrual periods, colds and sore throats, toothaches, backaches and to reduce fever. It is also used in combination medicines, which have more than one active ingredient to treat more than one symptom.

'Tis Cold and Flu Season

The National Institutes of Health (NIH) says that Americans catch one billion colds per year and as many as 20% of Americans get the flu. Moreover, 7 in 10 Americans use OTC medicines to treat cold, cough and flu symptoms.

Fathia Gibril, M.D., M.HSc., a supervisory medical officer at the Food and Drug Administration (FDA), explains that consumers looking for relief from a cold or the flu may not know that acetaminophen comes in combination with many other medications used to treat those symptoms. "So if you're taking more than one medicine at a time," she says, "you may be putting yourself at risk for liver damage."

Symptoms of acetaminophen overdose may take many days to appear, and even when they become apparent, they may mimic flu or cold symptoms. The current maximum recommended adult dose of acetaminophen is 4,000 milligrams per day, To avoid exceeding that dose:

• don't take more than one OTC product containing acetaminophen,
• don't take a prescription and an OTC product containing acetaminophen, and
• don't exceed the recommended dose on any product containing acetaminophen.

"When you're at the store deciding which product to buy, check the 'Drug Facts' label of OTC cold, cough and flu products before using two or more products at the same time," Gibril says. If you’re still not sure which to buy, ask the pharmacist for advice.

Rely on Health Care Experts

Acetaminophen is used in many commonly prescribed medications in combination with pain relievers such as codeine, oxycodone and hydrocodone. As of January 2011, FDA reported that overdoses from prescription medicines containing acetaminophen accounted for nearly half of all cases of acetaminophen-related liver injury in the U.S. When your health care professionals prescribe a drug, be sure to ask if it contains this active ingredient, and also to inform them of all other medicines (prescription and OTC) and supplements you take.

Even if you still have fever or pain, it's important not to take more than directed on the prescription or package label, notes FDA supervisory medical officer Sharon Hertz, M.D. But be careful, the word "acetaminophen" is not always spelled out in full on the container's prescription label. Abbreviations such as APAP, Acetaminoph, Acetaminop, Acetamin, or Acetam may be used instead.

When buying OTC products, Hertz suggests you make it a habit of telling the pharmacist what other medications and supplements you’re taking and asking if taking acetaminophen in addition is safe.

When the medicine is intended for children, the "Directions" section of the Drug Facts label tells you if the medicine is right for your child and how much to give. If a dose for your child's weight or age is not listed on the label and you can't tell how much to give, ask your pharmacist or doctor what to do.

If you're planning to use a medication containing acetaminophen, you should tell your health care professional if you have or have ever have had liver disease.

Acetaminophen and alcohol may not be a good mix, either, Hertz says. If you drink three or more alcoholic drinks a day, be sure to talk to your health care professional before you use a medicine containing acetaminophen.

Although most colds in children don’t cause serious complications, they can cause stress and worry in parents and caregivers. It’s understandable that you might want to give your child medicine to treat a cold. But most children will get better on their own, and cough or cold medicine will not change the natural course of a cold or make it go away faster.

In addition, some cough and cold medicines can have serious side effects, such as slowed breathing, which can be life-threatening, especially in infants and young children. For those reasons, it’s important to know when your child needs medication, which treatments are recommended, and when to do without medicine.

These days, cold and cough symptoms can be especially worrisome, because they could be symptoms of COVID-19, the flu, or other potentially serious illness. If you are concerned about COVID-19, talk to your child’s health care provider.

Ways to Treat Colds in Infants and Children

Coughs are a normal symptom of a cold and help the body clear the mucus out of the airway and protect the lungs. Non-drug treatments for coughs include drinking plenty of fluids, especially warm drinks to soothe the throat.

The U.S. Food and Drug Administration offers these tips for relieving cough and cold symptoms in infants and children:

A cool mist humidifier makes breathing easier by decreasing congestion in nasal passages. Do not use warm mist humidifiers because they can cause nasal passages to swell and make breathing more difficult.

Saline nose drops or sprays keep nasal passages moist and help avoid stuffiness.

Nasal suctioning with a bulb syringe or a similar product, with or without saline nose drops, works very well for children younger than a year old. You can use them on older children, too, but they often resist bulb syringes.

Acetaminophen or ibuprofen can be used to reduce fever, aches, and pain. Carefully read and follow the product’s instructions on the Drug Facts label or talk to your pharmacist or health care provider about dosage.

Encourage children to drink plenty of liquids to stay hydrated.

Giving Children Cough and Cold Medicines

Over-the-counter (OTC) medicines are available to treat cough and cold symptoms. The FDA doesn’t recommend OTC medicines for cough and cold symptoms in children younger than 2 because they could cause serious and potentially life-threatening side effects. Manufacturers voluntarily label these cough and cold products to state: “Do not use in children under 4 years of age.”

Numerous OTC cough and cold products contain many ingredients that can lead to accidental overdosing. Learn about what drugs (active ingredients) are in a product by reading the Drug Facts label.

Nonprescription cough and cold products can be harmful to children if:

• They get more than the recommended dose or take the medicine too often.
• They take more than one product containing the same drug. For example, taking both a pain reliever containing acetaminophen and cough and cold medicine containing acetaminophen.

How can you be sure to give the correct dose? The FDA encourages drug manufacturers to provide a dosing instrument, such as a syringe or a cup, marked with the correct measurements. Use them—and not household spoons or tools from other medications—to measure medication.

Don’t give children medicines that are packaged and made for adults because adult medicines may overdose a child.

There Are No FDA-Approved Homeopathic Products

At your pharmacy and online, you may see other cough and cold medicine being sold for children advertised as homeopathic. It’s important to note that these homeopathic products are drugs because they are intended to treat or mitigate colds, even though some of these products might look similar to dietary supplements.

Homeopathic products are generally labeled as containing very small amounts of highly diluted substances, including ingredients from plants, animal or human sources, bacteria, minerals, and chemicals. The FDA has found that some of these products contain active drug ingredients in levels that far exceed the amount stated on the product’s label, and could cause significant harm to children.

There are no FDA-approved homeopathic products, and homeopathic products sold in the U.S. have not met the FDA’s requirements for safety and effectiveness. The FDA is not aware of any proven benefits of these products and urges you not to give homeopathic cough and cold medicine to children younger than 4.

In certain instances, children younger than 4 who took these products have experienced serious side effects, some of which required hospitalization, including:

• Seizure, allergic reaction, and difficulty breathing.
• Low blood potassium and low blood sugar, which may result in headache, crankiness, drowsiness, and weakness.

These serious side effects occurred soon after children took a homeopathic cough and cold product; however, it is not always possible to know whether a reported side effect was caused by a medicine.

When to Call a Doctor

Not every sniffle or cough merits a trip to the doctor’s office. When in doubt, call your health care provider.

Some symptoms can signal that your child may have something more serious than a cold. For all children, call a doctor if you see any of these symptoms:

• A fever of 100.4 degrees Fahrenheit or higher in an infant 2 months or younger.
• A fever of 102 degrees Fahrenheit or higher in children at any age.
• Blue lips.
• Labored breathing, including nostrils widening with each breath; wheezing; fast breathing; the ribs showing with each breath; or shortness of breath.
• Severe headache.
• Not eating or drinking, with signs of dehydration (such as decreased urination).
• Excessive crankiness or sleepiness.
• Persistent ear pain.
• If the child is getting worse.

Codeine and tramadol are opioid medicines that may be used to treat pain. Codeine is also in some cough and cold remedies.

These medicines can cause life-threatening breathing problems in children. Some children and adults break down codeine and tramadol into their active forms faster than other people. That can cause the level of opioids in these people to rise too high and too quickly.

Nursing mothers who are taking codeine or tramadol can pass unsafe levels of opioids to their babies through breast milk. Those infants can become too sleepy, have difficulty breastfeeding, or have serious breathing problems.

Beware of Giving Kids Codeine or Tramadol

The FDA is warning that children younger than 12 shouldn’t take codeine products to treat pain or cough or tramadol to treat pain.

The FDA hasn’t approved tramadol for use in children. Kids younger than 18 shouldn’t take tramadol to treat pain after surgery to remove the tonsils (tonsillectomy) or adenoids (adenoidectomy). (Codeine labeling already warns that children should not be treated for post-surgery pain with codeine in these cases.)

Youths ages 12 through 18 who are obese or have obstructive sleep apnea (blocked airflow during sleep) or a weakened respiratory system shouldn’t take codeine or tramadol. These risk factors can increase their chances of serious breathing problems.

Tramadol is available only for adults and by prescription to treat pain. Codeine products are available by prescription and, in some states, over-the-counter (OTC). Codeine is often combined with acetaminophen in prescription pain medicines and with other cold medicines for treatment of cough.

Alternatives to Codeine and Tramadol

There are several alternatives for pain management in children, which you should discuss with your health care professional or pharmacist.

There are also alternative OTC and prescription medications available for cough. The FDA doesn’t recommend OTC cold and cough medicines for children younger than 2. Even in older children who have colds, coughs are generally mild and go away in a few days, so they may not need to take any medicine.

How to Know if Your Child’s Medicine Has Codeine or Tramadol

Read the label to make sure the medicine doesn’t have codeine or tramadol. Also, ask your health care provider or pharmacist if your medicine has codeine or tramadol.

Some over-the-counter (OTC) and prescription cough and cold medicines contain active ingredients that are psychoactive (mind-altering) at higher-than-recommended dosages and are frequently abused for this purpose. These products may also contain other drugs, such as expectorants and antihistamines, which are dangerous at high doses and compound the dangers of abuse.

Two commonly abused cough and cold medicines are:

• Dextromethorphan (DXM), a cough suppressant and expectorant found in many OTC cold medicines. It may produce euphoria and dissociative effects or even hallucinations when taken in quantities greater than the recommended therapeutic dose.

• Promethazine-codeine cough syrup, a medication that contains codeine, an opioid that acts as a cough suppressant and can also produce relaxation and euphoria when consumed at a higher-than-prescribed dose. It also contains promethazine HCl, an antihistamine that additionally acts as a sedative. Although only available by prescription, promethazine-codeine cough syrup is sometimes diverted for abuse.

How Are Cough and Cold Medicines Abused?

Cough and cold medicines are usually consumed orally in tablet, capsule, or syrup form. They may be mixed with soda for flavor and are often abused in combination with other drugs, such as alcohol or marijuana.

Because they are easily purchased in drugstores without a prescription, cough syrups, pills, and gel capsules containing DXM—particularly “extra strength” forms—are frequently abused by young people (who refer to the practice as “robotripping” or “skittling”). To avoid nausea produced by high doses of the expectorant guaifenesin commonly found in DXM containing syrups, young people may instead abuse Coricidin® HBP Cough & Cold capsules (street name C-C-C or triple-C), which contain DXM but lack guaifenesin.

Drinking promethazine-codeine cough syrup mixed with soda (a combination called syrup, sizzurp, purple drank, barre, or lean) was referenced frequently in some popular music beginning in the late 1990s and has become increasingly popular among youth in several areas of the country. A variation of “purple drank” is promethazine-codeine cough syrup mixed with alcohol. Users may also flavor the mixture with the addition of hard candies.

How Does Abusing Cough and Cold Medicines Affect the Brain?

When taken as intended, cough and cold medicines safely treat symptoms of lower and upper respiratory congestion and discomfort caused by colds and flu. But when taken in higher quantities or when such symptoms aren’t present, they may affect the brain in ways very similar to illegal drugs.

When taken in high doses, DXM acts on the same cell receptors as dissociative hallucinogenic drugs like PCP or ketamine. Users describe effects ranging from mild stimulation to alcohol- or marijuana-like intoxication, and at high doses, sensations of physical distortion and hallucinations.

Codeine attaches to the same cell receptors targeted by illegal opioids like heroin. Consuming more than the daily recommended therapeutic dose of promethazine-codeine cough syrup can produce euphoria similar to that produced by other opioid drugs; people addicted to codeine may consume several times the recommended, safe amount. Also, both codeine and promethazine HCl act as depressants of the central nervous system, producing sedating or calming effects.

When abused, both codeine and DXM directly or indirectly cause a pleasurable increase in the amount of dopamine in the brain’s reward pathway. Repeatedly seeking to experience that feeling can lead to addiction—a chronic relapsing brain disease characterized by inability to stop using a drug despite damaging consequences to a person’s life and health.

What Are the Other Health Effects of Abusing Cough and Cold Medicines?

Abusing DXM can cause impaired motor function, numbness, nausea or vomiting, increased heart rate and blood pressure, and at high doses, extreme agitation, increased body temperature, and a buildup of excess acid in body fluids. High doses of acetaminophen, a pain reliever commonly found with DXM, can cause liver damage. On rare occasions, hypoxic brain damage—caused by severe respiratory depression and a lack of oxygen to the brain—has occurred as a result of the combination of DXM with decongestants often found in the medication.

When abused, promethazine-codeine cough syrup presents a high risk of fatal overdose due to its effect of depressing the central nervous system, which can slow or stop the heart and lungs. Mixing with alcohol greatly increases this risk. Promethazine-codeine cough syrup has been linked to the overdose deaths of a few prominent musicians.

What’s the Bottom Line?

What do we know about the effectiveness of complementary approaches for flu and colds?

• No complementary health approach has been shown to be helpful for the flu.
• For colds:
  • Complementary approaches that have shown some promise include oral zinc products, rinsing the nose and sinuses (with a neti pot or other device), honey (as a nighttime cough remedy for children), vitamin C (for people under severe physical stress), probiotics, and meditation.
  • Approaches for which the evidence is conflicting, inadequate, or mostly negative include vitamin C (for most people), echinacea, garlic, and American ginseng.

What do we know about the safety of complementary approaches for colds and flu?

• People can get severe infections if they use neti pots or other nasal rinsing devices improperly. Tap water isn’t safe for use as a nasal rinse unless it has been filtered, treated, or processed in specific ways.
• Zinc products used in the nose (such as nasal gels and swabs) have been linked to a long-lasting or even permanent loss of the sense of smell.
• Using a dietary supplement to prevent colds often involves taking it for long periods of time. However, little is known about the long-term safety of some dietary supplements studied for prevention of colds, such as American ginseng and probiotics.
• Complementary approaches that are safe for some people may not be safe for others. Your age, health, special circumstances (such as pregnancy), and medicines or supplements that you take may affect the safety of complementary approaches.

Some Basics About Flu and Colds

Each year, Americans get more than 1 billion colds, and between 5 and 20 percent of Americans get the flu. The two diseases have some symptoms in common, and both are caused by viruses. However, they are different conditions, and the flu is more severe. Unlike the flu, colds generally don’t cause serious complications, such as pneumonia, or lead to hospitalization.

No vaccine can protect you against the common cold, but vaccines can protect you against the flu. Everyone over the age of 6 months should be vaccinated against the flu each year. Vaccination is the best protection against getting the flu.

Prescription antiviral drugs may be used to treat the flu in people who are very ill or who are at high risk of flu complications. They’re not a substitute for getting vaccinated. Vaccination is the first line of defense against the flu; antivirals are the second. If you think you’ve caught the flu, you may want to check with your health care provider to see whether antiviral medicine is appropriate for you. Call promptly. The drugs work best if they’re used early in the illness.

What the Science Says About Complementary Health Approaches for the Flu

No complementary approach has been shown to prevent the flu or relieve flu symptoms.

Complementary approaches that have been studied for the flu include the following. In all instances, there’s not enough evidence to show whether the approach is helpful.

• American ginseng
• Chinese herbal medicines
• Echinacea
• Elderberry
• Green tea
• Oscillococcinum
• Vitamin C
• Vitamin D

What the Science Says About Complementary Health Approaches for Colds

The following complementary health approaches have been studied for colds:

American Ginseng

• Several studies have evaluated the use of American ginseng (Panax quinquefolius) to prevent colds. A 2011 evaluation of these studies concluded that the herb has not been shown to reduce the number of colds that people catch, although it may shorten the length of colds. The researchers who conducted the evaluation concluded that there was insufficient evidence to support the use of American ginseng for preventing colds.
• Taking American ginseng in an effort to prevent colds means taking it for prolonged periods of time. However, little is known about the herb’s long-term safety. American ginseng may interact with the anticoagulant (blood thinning) drug warfarin.

Echinacea

• At least 24 studies have tested echinacea to see whether it can prevent colds or relieve cold symptoms. A comprehensive 2014 assessment of this research concluded that echinacea hasn’t been convincingly shown to be beneficial. However, at least some echinacea products might have a weak effect.
• One reason why it’s hard to reach definite conclusions about this herb is that echinacea products vary greatly. They may contain different species (types) of the plant and be made from different plant parts (the above-ground parts, the root, or both). They also may be manufactured in different ways, and some products contain other ingredients in addition to echinacea. Research findings on one echinacea product may not apply to other products.
• Few side effects have been reported in studies of echinacea. However, some people are allergic to this herb, and in one study in children, taking echinacea was linked to an increase in rashes.

Garlic

• A 2014 evaluation of the research on garlic concluded that there isn’t enough evidence to show whether this herb can help prevent colds or relieve their symptoms.
• Garlic can cause bad breath, body odor, and other side effects. Because garlic may interact with anticoagulant drugs (blood thinners), people who take these drugs should consult their health care providers before taking garlic.

Honey

• Honey’s traditional reputation as a cough remedy has some science to back it up. A small amount of research suggests that honey may help to decrease nighttime coughing in children.
• Honey should never be given to infants under the age of 1 year because it may contain spores of the bacterium that causes infant botulism. Honey is considered safe for older children.

Meditation

• Reducing stress and improving general health may protect against colds and other respiratory infections. In a 2012 study funded by the National Center for Complementary and Integrative Health (NCCIH), adults aged 50 and older were randomly assigned to training in mindfulness meditation, which can reduce stress; an exercise training program, which may improve physical health; or a control group that didn’t receive any intervention. The study participants kept track of their illnesses during the cold and flu season. People in the meditation group had shorter and less severe acute respiratory infections (most of which were colds) and lost fewer days of work because of these illnesses than those in the control group. Exercise also had some benefit, but not as much as meditation.
• This study is the first to suggest that meditation may reduce the impact of colds. Because it’s the only study of its kind, its results shouldn’t be regarded as conclusive.
• Meditation is generally considered to be safe for healthy people. However, there have been reports that it might worsen symptoms in people with certain chronic physical or mental health problems. If you have an ongoing health issue, talk with your health care provider before starting meditation.

Probiotics

• A 2015 evaluation of 13 studies found some evidence suggesting that probiotics might reduce the number of colds or other upper respiratory tract infections that people catch and the length of the illnesses, but the quality of the evidence was low or very low.
• In people who are generally healthy, probiotics have a good safety record. Side effects, if they occur at all, usually consist only of mild digestive symptoms such as gas. However, information on the long-term safety of probiotics is limited, and safety may differ from one type of probiotic to another. Probiotics have been linked to severe side effects, such as dangerous infections, in people with serious underlying medical problems.

Saline Nasal Irrigation

• Saline nasal irrigation means rinsing your nose and sinuses with salt water. People may do this with a neti pot (a device that comes from the Ayurvedic tradition) or with other devices, such as bottles, sprays, pumps, or nebulizers. Saline nasal irrigation may be used for sinus congestion, allergies, or colds.
• There’s limited evidence that saline nasal irrigation can help relieve cold symptoms. Studies of this technique have been too small to allow researchers to reach definite conclusions.
• Saline nasal irrigation used to be considered safe, with only minor side effects such as nasal discomfort or irritation. However, in 2011, a severe disease caused by an amoeba (a type of microorganism) was linked to nasal irrigation with tap water. The U.S. Food and Drug Administration (FDA) has warned that tap water that is not filtered, treated, or processed in specific ways is not safe for use in nasal rinsing devices and has explained how to use and clean these devices safely.

Vitamin C

• An evaluation of the large amount of research done on vitamin C and colds (29 studies involving more than 11,000 people) concluded that taking vitamin C doesn’t prevent colds in the general population and shortens colds only slightly. Taking vitamin C only after you start to feel cold symptoms doesn’t affect the length or severity of the cold.
• Unlike the situation in the general population, vitamin C does seem to reduce the number of colds in people exposed to short periods of extreme physical stress (such as marathon runners and skiers). In studies of these groups, taking vitamin C cut the number of colds in half.
• Taking too much vitamin C can cause diarrhea, nausea, and stomach cramps. People with the iron storage disease hemochromatosis should avoid high doses of vitamin C. People who are being treated for cancer or taking cholesterol-lowering medications should talk with their health care providers before taking vitamin C supplements.

Zinc

• Zinc has been used for colds in forms that are taken orally (by mouth), such as lozenges, tablets, or syrup, or used intranasally (in the nose), such as swabs or gels.
• Oral Zinc
  • A 2012 evaluation of 17 studies of various types of zinc lozenges, tablets, or syrup found that zinc can reduce the duration of colds in adults. Two evaluations of three studies of high-dose zinc acetate lozenges in adults, conducted in 2015 and 2016, found that they shortened colds.
  • Some participants in studies that tested zinc for colds reported that the zinc caused a bad taste or nausea.
  • Long-term use of high doses of zinc can cause low copper levels, reduced immunity, and low levels of HDL cholesterol (the “good” cholesterol). Zinc may interact with drugs, including antibiotics and penicillamine (a drug used to treat rheumatoid arthritis).
• Intranasal Zinc
  • The use of zinc products inside the nose, such as gels or swabs, may cause loss of the sense of smell, which may be long-lasting or permanent. In 2009, the FDA warned consumers to stop using several intranasal zinc products marketed as cold remedies because of this risk.
  • Prior to the warnings about effects on the sense of smell, a few studies of intranasal zinc had suggested a possible benefit against cold symptoms. However, the risk of a serious and lasting side effect outweighs any possible benefit in the treatment of a minor illness.

Other Complementary Approaches

In addition to the complementary approaches described above, several other approaches have been studied for colds. In all instances, there is insufficient evidence to show whether these approaches help to prevent colds or relieve cold symptoms.

• Andrographis (Andrographis paniculata)
• Chinese herbal medicines
• Green tea
• Guided imagery
• Hydrotherapy
• Vitamin D
• Vitamin E

NCCIH-Funded Research

NCCIH-supported researchers are conducting a variety of studies relevant to the flu or colds.

Topics of recent research include:

• Whether probiotics can enhance older adults’ response to flu vaccine
• Meditation and exercise for preventing acute respiratory infection
• How psychosocial factors, such as the quantity and quality of social relationships, influence the likelihood of catching colds
• The effects of echinacea on the immune system.

More To Consider

• Complementary health approaches should never be used as a substitute for flu vaccination.
• Tell all your health care providers about any complementary health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care

It’s that time of year again—cold and flu season.

Each year, approximately 5 to 20 percent of Americans come down with the flu. Although most recover without incident, flu-related complications typically lead to at least 200,000 hospitalizations and between 12,000 and 60,000 deaths each year. Colds generally do not cause serious complications, but they are among the leading reasons for visiting a doctor and for missing school or work.

Some people try natural products such as herbs or vitamins and minerals to prevent or treat these illnesses. But do they really work? What does the science say?

1. Vaccination is the best protection against getting the flu. Starting in 2010, the Federal Government’s Centers for Disease Control and Prevention has recommended annual flu vaccination for all people aged 6 months and older.
   
   There is currently no strong scientific evidence that any natural product is useful against the flu.

2. Zinc taken orally (by mouth) may help to treat colds, but it can cause side effects and interact with medicines. Zinc is available in two forms—oral zinc (e.g., lozenges, tablets, syrup) and intranasal zinc (e.g., swabs and gels). A 2015 analysis of clinical trials found that oral zinc helps to reduce the length of colds when taken within 24 hours after symptoms start. Intranasal zinc has been linked to a severe side effect (irreversible loss of the sense of smell) and should not be used.
   
   A note about safety:Oral zinc can cause nausea and other gastrointestinal symptoms. Long-term use of zinc, especially in high doses, can cause problems such as copper deficiency. Zinc may interact with drugs, including antibiotics and penicillamine (a drug used to treat rheumatoid arthritis).

3. Vitamin C does not prevent colds and only slightly reduces their length and severity. A 2013 review of scientific literature found that taking vitamin C regularly did not reduce the likelihood of getting a cold but was linked to small improvements in cold symptoms. In studies in which people took vitamin C only after they got a cold, vitamin C did not improve their symptoms.
   
   A note about safety:Vitamin C is generally considered safe; however, high doses can cause digestive disturbances such as diarrhea and nausea.

4. Echinacea has not been proven to help prevent or treat colds. Echinacea is an herbal supplement that some people use to treat or prevent colds. Echinacea products vary widely, containing different species, parts, and preparations of the echinacea plant. Reviews of research have found limited evidence that some echinacea preparations may be useful for treating colds in adults, while other preparations did not seem to be helpful. In addition, echinacea has not been shown to reduce the number of colds that adults catch. Only a small amount of research on echinacea has been done in children, and the results of that research are inconsistent.
   
   A note about safety: Few side effects have been reported in clinical trials of echinacea; however, some people may have allergic reactions. In one large clinical trial in children, those who took echinacea had an increased risk of developing rashes.

5. The evidence that probiotic supplements may help to prevent colds is weak, and little is known about their long-term safety. Probiotics are a type of “good bacteria,” similar to the microorganisms found in the body, and may be beneficial to health. Probiotics are available as dietary supplements and yogurts, as well as other products such as suppositories and creams. Although a 2015 analysis of research indicated that probiotics might help to prevent upper respiratory tract infections, such as the common cold, the evidence is weak and the results have limitations.
   
   A note about safety:Little is known about the effects of taking probiotics for long periods of time. Most people may be able to use probiotics without experiencing any side effects—or with only mild gastrointestinal side effects such as gas —but there have been some case reports of serious side effects. Probiotics should not be used by people with serious underlying health problems except with close monitoring by a health care provider.