Practitioners of complementary and alternative medicine (CAM) use health care practices and products that are not considered a part of the conventional medicine practiced by holders of MD (medical doctor), DO (doctor of osteopathy), nursing and therapy degrees. The list of treatments considered CAM evolves regularly as therapies that are proven to be safe and effective in clinical trials become mainstream health care. It is not unusual for an individual to use complementary medicine and conventional medicine at the same time.

The ginkgo tree is one of the oldest types of trees in the world. In Western medicine, ginkgo is receiving attention for its potential role in the treatment of memory disorders and dementias, especially Alzheimer's disease. It may also be effective in alleviating blood vessel diseases, most notably poor circulation to the lower legs (intermittent claudication). Other uses being studied are dizziness (vertigo) and ringing in the ears (tinnitus). The potential pharmacological effects of ginkgo include antioxidant activity, inhibition of platelet aggregation and vasodilation.

Asian ginseng is native to China and Korea and has been used for many centuries. True ginsengs include Asian ginseng and American ginseng. An herb called Siberian ginseng or eleuthero (Eleutherococcus senticosus) is not a true ginseng.

Huperzine A, or qian ceng ta, is an extract from Chinese club moss (Huperzia serrata) that has been used for treating dementia and myasthenia gravis in China. It is promoted in the US as a memory-enhancing supplement.

In February 2004, the US Food and Drug Administration (FDA) prohibited the sale of dietary supplements containing ephedrine alkaloids (ephedra) because such supplements present an unreasonable risk of illness or injury. It may still be found in some products manufactured outside the US and either imported illegally or purchased abroad.

Ephedra, or ma huang, is a shrub-like plant that is found in desert regions in central Asia and other parts of the world. It is a stimulant containing the herbal form of ephedrine. The main active ingredient in ephedra is an amphetamine-like compound make up of the alkaloids ephedrine and pseudoephedrine that can powerfully stimulate the nervous system and heart.

• The National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health (NIH) (888) 644-6226
• The Office of Dietary Supplements (ODS) at the National Institutes of Health (NIH) (301) 435-2920
• Natural Standard Database An international research collaboration that aggregates and synthesizes data on complementary and alternative therapies.
• Natural Medicines Comprehensive Database (consumer version) Provides easy-to-understand information on herbal remedies, dietary supplements, vitamins, minerals, and other natural products.
• ConsumerLab.com Provider of independent test results and information on health, wellness and nutrition products (888) 502-5100