Zinc lozenges reduce the duration of common cold symptoms.

A randomized, double-blind, placebo-controlled clinical trial has shown that treatment of the common cold with zinc gluconate lozenges resulted in a significant reduction in duration of symptoms of the cold. Patients received zinc-containing lozenges or placebo lozenges every 2 hours for the duration of cold symptoms. The median time to complete resolution of cold symptoms was 4.4 days in the zinc group compared with 7.6 days in the placebo group. The mechanism of action of zinc in treating the common cold remains unknown.