Alternative medicine

A number of products have claimed to help fend off common illnesses, such as the cold or flu. While some of these substances have appeared promising in early trials, follow-up studies may have had conflicting or inconclusive results. More research needs to be done.

Some of the substances that have been studied for preventing or shortening the duration of infection include:

• Cranberry
• Echinacea
• Garlic
• Ginseng
• Goldenseal
• Vitamin C
• Vitamin D
• Zinc

Check with your doctor before trying any products that promise to boost your immune system or chase colds and other illnesses away. Some of these products may cause allergic reactions or interact adversely with other medications you may be taking.