Pharmacies stock hundreds of cold and cough remedies, including natural treatments and preventives, such as zinc and vitamin C. But which ones really work?

One proven way to prevent colds is to wash your hands frequently. You don't have to be around people who are coughing or sneezing to get sick-a person can be ill with a cold for 24 hours before symptoms start.

Best: Assume that you've been exposed-and wash your hands before viruses have a chance to enter the mucous membranes in your nose, eyes or mouth. If you are unable to wash your hands, use waterless hand sanitizers containing alcohol instead.

Unfortunately, not all cold preventives and remedies are so effective. Here's the real story about common cold remedies..


A recent study published in The Lancet analyzed the findings of 14 previous studies and reported that the herb echinacea reduced the risk of catching a cold by 58% and also shortened the duration of a cold. Yet previous research, including a large study published in The New England Journal of Medicine, found that echinacea doesn't make a significant difference.

A number of factors might explain the conflicting results. It's possible that some, but not all, cold viruses are susceptible to echinacea. Also, because the US Food and Drug Administration doesn't regulate herbal products, the doses and quality of echinacea-and even the species-may vary from study to study, affecting results.

My conclusion: Echinacea might have a minor effect on cold treatment and prevention, but the evidence is too weak to recommend it. It is one of the safer herbs, though, so apart from the modest expense, there is no downside to trying it.

Vitamin C

More than 35 years ago, Nobel prizewinner Linus Pauling suggested that large doses of vitamin C—1,000 milligrams (mg) or more daily—could prevent a cold. Research since then has been inconsistent. Some studies indicate that vitamin C can reduce the duration and severity of cold symptoms and possibly aid in prevention. Other studies find no benefits.

Latest finding: Researchers looked at 30 previous clinical studies, which included a total of 11,350 participants. They concluded that vitamin C does not prevent colds. However, they also noted that patients with colds who took at least 200 mg of vitamin C daily did experience a slight reduction in cold symptoms and duration.

My conclusion: Vitamin C appears to reduce cold symptoms, but the improvement is so modest that many people won't notice the difference. Higher doses do not appear to help... and taking more than 200 mg daily increases the risk of kidney stones and diarrhea.

Important: Drink two extra glasses of water daily when taking vitamin C. It helps prevent kidney stones and moistens mucous membranes, which is helpful for reducing cold symptoms.

Zinc Lozenges

Despite their unpleasant taste, zinc lozenges were popular in the 1990s. Early studies indicated that they could significantly shorten the duration of colds. Newer evidence, however, has shown that they probably are not effective. Other forms of zinc, including zinc-treated nasal swabs, are still being investigated.

My conclusion: Zinc lozenges are not effective for cold treatment or prevention.


Oral, long-lasting decongestants (which contain pseudoephedrine), such as Sudafed, and short-acting nasal sprays (which contain oxymetazoline), such as Afrin, work in a similar fashion. By shrinking blood vessels in the nose and sinuses, they reduce congestion, but they can cause side effects, including insomnia and the "jitters," in some people. They also occasionally cause an increase in blood pressure. Using them for more than a few days often results in rebound congestion-inflammation of the mucous membranes that increases stuffiness.

My conclusion: Decongestants don't shorten the duration of colds, but they are very effective at reducing stuffiness-the sprays work almost instantly. To limit side effects, use them for no more than 72 hours at a stretch.

Cough Suppressants

Most over-the-counter OTC) cough suppressants contain dextromethorphan, a chemical that is supposed to suppress the cough reflex but that doesn't work all that well. Suppressants that contain codeine are far more effective, but they are available only with a prescription. Doctors prescribe cough suppressants for a dry, nagging cough, particularly if it's keeping you up at night. You do not want to suppress a productive cough, which can help remove mucus from the airways.

My conclusion: OTC cough suppressants give only modest relief. Stronger drugs, available by prescription, are a better choice for people with serious, persistent coughs.


They're a common ingredient in combination cough and cold remedies. Antihistamines dry mucous membranes and provide some relief from sneezing and/or a runny nose. However, their main effect is to block the effects of histamine, a chemical that's produced by allergies, not colds.

My conclusion: Don't take antihistamines for colds. They don't work. In fact, they can thicken cold secretions and make symptoms worse.

Staying Warm

Will being cold cause you to get a cold? A few years ago, a study published in Family Practice found that 29% of volunteers who were chilled (they submerged their feet in icy water for 20 minutes) caught a cold, compared with less than 10% of participants in a "warm" group.

Study flaw: The two groups of volunteers weren't confined in one place after the experiment, so there was no way to tell if people in both groups were exposed equally to cold viruses later

Earlier studies conducted in England did control for exposure. Volunteers were either chilled or not, then deliberately exposed to the same number of cold viruses. These studies showed that cold temperatures had no effect on the incidence of colds.

My conclusion: Staying warm will not prevent a cold.

Ugh! Hidden Bacteria

Mouth guards often harbor bacteria, yeasts and molds that can cause serious health problems, including oral sores, difficulty breathing, nausea, vomiting and diarrhea. Rinsing or scrubbing mouth guards (worn overnight for problems such as teeth grinding) does not kill these microorganisms. Researchers are working to develop effective disinfection.

Self-defense: Use a disposable mouth guard ($150 to $2 apiece at a pharmacy or sporting-goods store), and toss after a week of use.

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