Mayo Clinic http://www.mayohealth.org
This site maintains a searchable index of drugs currently available in the US.

National Institutes of Health: http://www.medlineplus.gov
The National Institutes of Health maintain a searchable site with details about drugs currently available in the US as well as drugs which are currently under development and seeking federal approval.

American Society of Health-System Pharmacists http://www.safemedication.com
Website with a search engine to find information about any drug that you are interested in.

The US governments Food and Drug Administration (FDA) maintains a website with information on drugs and supplements, as well as information about what claims a specific product may make: http://www.fda.gov.

Books:

Tyler's Honest Herbal, by Steven Foster and Varro E. Tyler (Binghampton, NY: The Hayworth Press, Inc., 1999).
Two experts on herbs and their medicinal uses provide a fair and concise summary of the risks and benefits of more than 120 herbal remedies.

The Physician's Desk Reference for Nutritional Supplements, by Sheldon Saul Hendler Ph.D., M.D., and David Rorvik. (Montvale, NJ: The Medical Economics Company, Inc., 2001, 700 pp., $59.95). This frank and science-based book reviews the scientific evidence for ginkgo biloba and other herbal remedies.

Published Articles:

"Dietary supplements: Nutritional and legal considerations," by Mary Ellen Camire and Mark A. Kantor. (Food Technology, vol. 53, no. 7, July 1999).
This is a report in a technical journal which summarizes what scientists currently know about the role of vitamins, herbals and other dietary supplements in human health.

"Cholinesterase inhibitors: A therapeutic strategy for Alzheimer's disease," by W. Krall, J. Sramek, N. Cutler (Annals of Pharmacotherapy, 1999, vol. 33, p. 441-450).
This is a technical article in a scientific journal which contains a comprehensive review of the class of drugs (cholinesterase inhibitors) which includes all the drugs currently marketed in the US as treatment for Alzheimer's disease.

B. Oken and others, "The efficacy of ginkgo biloba on cognitive function in Alzheimer disease," in Archives of Neurology, November 1998, vo. 55, no. 11, pp. 1409-1415.

"A placebo-controlled, double-blind, randomized trial of an extract of ginkgo biloba for dementia," by the North American EGb Study Group, in Journal of the American Medical Association, October 1997, vol. 278, no. 16, pp. 1327-1332.

"The efficacy of ginkgo for elderly people with dementia and age-associated memory impairment: new results of a randomized clinical trial," by M. van Dongen and others, in Journal of the American Geriatric Society, October 2000, vol. 48, no. 10, pp. 1183-1194.

"A 26-week analysis of a double-blind, placebo-controlled trial of the ginkgo biloba extract EGb 761 in dementia," by P. Le Bars and others, in Dementia and Geriatric Cognitive Disorders, July-August 2000, vol. 11, no. 4, pp. 230-237.