The common cold is caused by more than 300 serologically distinct viruses. Since there are so many different types, it is impossible to develop a single vaccine effective against them all.
A randomized, double-blind, placebo-controlled clinical trial has shown that zinc gluconate lozenges produce a reduction in the duration of cold symptoms. In this study, patients received zinc 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 (Anon. 1997).
Another study to test the benefits of zinc gluconate lozenges showed that the time to complete resolution of symptoms was significantly shorter in the zinc group than in the placebo group. The zinc group had significantly fewer days with coughing, headache, hoarseness, nasal congestion, nasal drainage, and sore throat (Mossad et al. 1996). By dissolving two zinc lozenges in the mouth every few hours, the zinc will help inactivate cold viruses multiplying in the throat.
Scientific research shows that garlic is a source of phytochemicals that protects against infection and inflammation, lowers the risk of heart disease, and has anticancer effects. Garlic is rich in antioxidants that include organosulfur compounds and flavonoids, capable of scavenging free radicals. Garlic also contains selenium, which is required for the antioxidant enzyme glutathione peroxidase. These properties help to enhance the immune system in fighting off infections caused by bacteria, viruses, and fungi.
Human studies (Abdullah 1989) confirm immune stimulation by garlic. Subjects receiving aged garlic extract at 1800 mg a day for 3 weeks showed a 155.5% increase in immune cell activity. Garlic and garlic preparations increase the activity of immune cells, including macrophages that kill infectious invaders.