Pathology-The primary barrier to using pharmacologic or immunologic agents to prevent or treat the common cold is that no single specific pathogen causes it. The common cold can be caused by a number of different pathogens. The most common of these is a group of rhinoviruses; they still only account for 30% to 40% of colds seen clinically, however. Different types of influenza viruses also can cause syndromes synonymous with the common cold and are reported to be responsible for 25% to 30% of all colds. Other pathogens include coronaviruses, adenoviruses, parainfluenza viruses, and respiratory syncytial viruses.* Prevention-Dietary Supplements Dietary supplements, which broadly include vitamins, minerals, and botanicals, are becoming increasingly popular for the prevention and treatment of the common cold. The main dietary supplements commonly used today for the prevention and/or treatment of the common cold include vitamin C, echinacea, and zinc. These products are widely available throughout most pharmacies, but the FDA has not evaluated the use of these or other dietary supplements for their stated label claims. As such, manufacturers of dietary supplements must place the following statement on the label: "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.* Treatment- Vitamin C The role of vitamin C (ascorbic acid) in the prevention of the common cold is not completely understood, but it appears to act as an immune-stimulating agent by helping cells of the immune system mature. Vitamin C also may protect against cellular stress, as the concentration of vitamin C in immune cells appears to be high.* Echinacea Echinacea, a plant with purported medicinal properties, is another popular supplement that is often used to help manage the common cold.Echinacea is thought to stimulate the body's immune system through effects on T-lymphocytes, macrophages, and natural killer cells, thereby helping the body to fight infection. Echinacea also is claimed to have antibacterial, antifungal, and antiviral properties.28 The use of echinacea for the prevention or treatment of the common cold is controversial, with current studies showing mixed results. In a recent Cochrane review of randomized controlled trials evaluating the use of echinacea versus placebo for prevention, no statistically significant difference was found in terms of the number of colds, their severity, or duration for the 2 trials that fit the study's inclusion criteria.* Zinc Zinc is another popular product that is often used to help treat the common cold. It is widely available in many dosage forms, including lozenges, sprays, swabs, and gums (Table 2). Zinc's mechanism of action is not quite fully understood. In vitro, zinc salts inhibit rhinovirus replication.* *information from Pharmacy times ACPE : 290-000-08-010-H01-P