clipped from: www.examiner.com 
1. Echinacea
Generally used at the first sign of a cold as an immune system stimulant. It isn’t appropriate for long-term use and shouldn’t be used by people on immunosuppressants.
2. Ginseng
Gineng is used for many purposes, often relating to alertness, energy and mental functioning. Some people believe that it can stimulate the immune system and possibly even decrease the risk of cancer.
3. Garlic
Garlic is often used to decrease cholesterol and high blood pressure. It may also thin the blood and can interact with other blood thinners. There is some evidence that regular use of garlic may decrease the risk of cancer.
4. Ginko Biloba
Ginko is generally used for memory loss and dementia syndromes such as Alzheimer’s disease.
5. St. John’s Wort
St. John’s Wort is sometimes thought of as ‘mini-Prozac’ and is used for mild depression.