Cold remedies with mixed study results

In spite of ongoing studies, the scientists still don't know whether some cold remedies, such as vitamin C and zinc, work. Here's what studies show:

Vitamin C

Taking vitamin C has not been shown to help prevent colds.

But some studies have found that taking vitamin C before cold symptoms start may shorten how long symptoms last. Vitamin C may help people at high risk of colds because they're often in contact with the viruses that cause colds. For instance, children who go to group child care during the winter are at high risk.

Zinc

Some studies show that zinc lozenges or syrup may prevent a cold or shorten symptoms. Other studies show zinc doesn't help.

Zinc can have harmful side effects.

The U.S. Food and Drug Administration advises against using products with zinc you put in your nose. They can cause you to lose your sense of smell. Talk with your healthcare professional before using zinc.