MedLine Plus

National Library of Medicine. Links to many good subsidiary sites. Best starting point.

Health Web

Reliable information selected by professionals.

Web MD

Very comprehensive information on medical conditions.

Merck Home Edition

Recommended, although sometimes highly technical.

Healthfinder (U.S. Government Site)

Unbiased and thorough.

PDR

Requires registration.

DrugFacts.Com

Confusing to navigate and covers only the most common drugs.

CDC Diseases and Health Directory

NIH Directory of Health Topics

Dr. Koop

Some good information but heavily loaded with ads, including pop-up windows.

FDA

FDA

Alternate FDA site.

Dr. Dean Edell

Lots of good information, but buried among advertising.

AHCN: Health Information Index & Search

National Center for Alternative and Complementary Medicine

NIH Office of Drug Supplements

Not much practical information.

California HealthCare Foundation

Life Extension Foundation

Look at Life Extension Discounts.

Vision Service Plan

Kaiser Medical Plan

Legs for Life

Info on peripheral vascular disease.