1) Vitamin C Cold Home Remedy
In 1970 Linus Pauling, 2-time Nobel Prize winner, stated that vitamin C alleviates and prevents the common cold. Over the past thirty years, a number of studies have been performed to determine the benefits of vitamin C in treating and preventing the common cold. A recent study of the current published literature indicates a significant reduction in the length and severity of illness 23% (J Am Coll Nutr 14:116, 1995). The potential benefits from taking vitamin C might be greatest in persons with insufficient dietary vitamin C intake--which would be most Americans because they eat too few vegetables and fruits. There is no vitamin C in dairy, poultry, meat or any other animal product. Refined foods have had most of the vitamin C removed. A suffiecient dose for supplementation is not determined, but is most likely greater than 1 gram a day.

Vitamin C

2) Echinacea and Ginseng
Several herbs, such as Echinacea and Ginseng , are thought to help stop colds and flu. In a multi-centre, two-branch, placebo-controlled, randomized, double-blind investigation a total of 227 persons took daily oral  dose capsules of either placebo or 100 milligrams of standardized ginseng extract Ginsana G 115 for a time period of 12 weeks. Within this period they also received an anti-influenza polyvalent vaccination at week 4 Drugs Exp Clin Res 1996;22(2):65-72. There were 42 incidents of  flu or colds in the placebo group, but there were only 15 cases in the G115 group. Antibody titres combating the flu virus by the 8th week rose to an average of 171 units in the placebo group.  They rose to an average of 272 units in the G115 group. Natural killer (NK) activity levels in the 8th week and 12th week were nearly double the G115 group when compared to the placebo group.

3) Echinacea
A plant originally used by Native Americans, Echinacea purpurea, to treat respiratory and lung infections, has been shown to stimulate the manufacture of antiviral factors by human white blood cells (Int J Immunopharmacol 1997 Jul;19(7):371-9). Even minute doses (0.012 microgram/ml) had the same effect. These findings support the proposed preventive effects of Echinacea on flu and colds flu.  My personal plan is to take Echinacea and vitamin C with the first suggestion that I might have contacted a virus or the first symptom of a flu or cold.
 
4) Zinc as Cold Home Remedy
There have been no less than 8 controlled clinical trials that have been published on zinc as a treatment for the common cold.  Four of these indicated benefit while four did not (Ann Pharmacother 32:63, 1999; Ann Intern Med 125:81, 1996). The variation in results could be due to variation in dosages and formulations.  Zinc gluconate lozenges are possibly more effective than lozenges made with tartaric acid and citric acid which bind zinc making it unabsorbable.  The exact method of action is not known, however zinc may act by stopping the virus from attaching to the cells of the respiritory tract.  This would prevent the virus from engaging and entering the cells.  The benefit seems to be most pronounced if the lozenges are taken immediately as symptoms appear.