Smithsonian.com

The common cold is not fun. When I get one, my head aches, my nose runs, my throat hurts and I cough for days. My mother tells me to drink orange juice and other liquids. Co-workers advise zinc or echinacea. And posters in the Metro system shill for a cold remedy full of vitamin C. Do any of these work?

Neither the Vitamin C nor the liquid in orange juice will help cure a cold (courtesy of flickr user mhaithaca)

Vitamin C: Double Nobel-winner Linus Pauling is responsible for popularizing the idea that high doses of Vitamin C could reduce the likelihood of catching a cold. But when put to the test, there has been little evidence that he was right. At best, you’d have to take a high dose of the stuff every day of the year to see a cold reduced in length from 12 days to 11 days. Tissues are cheaper.

Echinacea: Native Americans used the roots of Echinacea angustifolia to treat wounds and infections. Sometime in the late 1800s, people started using echinacea to treat the common cold. But when scientists tested various extracts of the plant to see whether it could treat or prevent colds, they found no statistically significant effects on either the rates of infection or severity of symptoms. (Critics argued that none of the doses were strong enough.)

Zinc: Zinc deficiency can hamper the immune system, so supplementing yourself with zinc would seem to be a good way to boost immune function. There are zinc lozenges and nasal sprays and gels. But the lozenges haven’t proven successful in clinical tests, and the FDA issued a warning on the nasal sprays and gels last year after users reported that the products harmed their sense of smell.

Antibiotics: The common cold is a viral disease so antibiotics, which work only on bacteria, just won’t help. Worse, overuse of antibiotics is contributing to the growing problem of antibiotic-resistant bacteria.

Liquids: Drinking extra juice and water is supposed to replace fluids in the body lost to fever and to help break up mucus. This has never been tested in a clinical trial, but studies of children with pneumonia found a real danger in the form of hyponatraemia, low levels of sodium in the blood, from drinking too much.

Chicken Soup: It works! Chicken soup has been a cold remedy since the time of the Greeks, but there’s more than folklore to back this up. In 2000, University of Nebraska scientists reported that chicken soup inhibited the ability of white blood cells caused neutrophils to cause inflammation, the cause of many of a cold’s miseries. (You’ll find the researcher’s wife’s recipe here.)