However, review of the data reported from individual trials showed a clinically important reduction in the duration of cold symptoms when doses of 10 to 23 mg zinc every 2 waking hours were used. Treatment of the common cold. Its summary points include the following. Alleviation of symptoms remains the only proven way to treat the common cold. First generation antihistamines and anticholinergics effectively reduce rhinorrhea and sneezing, but have minimal effects on other symptoms.
Antitussive agents are probably of minimal benefit.
Zinc may reduce the duration and intensity of symptoms but a safe effective dose is not yet established. There appeared to be a modest benefit from ingestion of relatively high doses of vitamin C in reducing duration of cold symptoms.