Immune System Effects of Echinacea,

Traditional herbal medicine provides several remedies for strengthening the body’s resistance to illness through effects on immune system components. This review article exam-ines 3 popular herbal immune stimulants that are often of in-terest to cancer patients. Echinacea, a native of North America, is widely used to prevent, or provide early treat-ment for, colds. Preclinical studies lend biological plausibil-ity to the idea that echinacea works through immune mechanisms. Numerous clinical trials have been carried out on echinacea preparations: it appears that the extracts shorten the duration and severity of colds and other upper respiratory infections (URIs) when given as soon as symp-toms become evident. However, trials of long-term use of echinacea as a preventive have not shown positive results. Ginseng has been studied in some depth as an antifatigue agent, but studies of immune mechanisms have not pro-ceeded so far. Preclinical evidence shows some immune-stimulating activity. There have been several clinical trials in a variety of different diseases. Astragalus is the least-studied agent. There are some preclinical trials that show intriguing immune activity. The herbs discussed appear to have satis-factory safety profiles. Cancer patients may wish to use these botanicals to inhibit tumor growth or to boost resistance to infections. However, passive immunotherapy with herbs, with no mechanism to expose tumor antigens, is unlikely to be effective in inhibiting tumor growth. Although the margin of safety for these herbs is large, more research is needed to demonstrate the clear value of using herbs to improve resis-tance to infections