Healthfinder
For government and nonprofit health and human services information. Developed by the U.S. Department of Health and Human Services together with other federal agencies.
www.healthfinder.gov

MEDLINEplus
For health information from the world's largest medical library. Provides information on over 600 diseases and conditions, hospitals and physicians, a medical encyclopedia and dictionary, health information in Spanish, prescription and nonprescription drugs. A service of the U.S. National Library of Medicine and the National Institutes of Health.
www.nlm.nih.gov/medlineplus/tutorial.html

National Institutes of Health
From the U.S. government department in charge of medical research, provides health information on biomedical and behavioral research, grants and funding opportunities, news, scientific resources institutes, etc.
www.nih.gov

WebMD
Provides consumer-focused healthcare information and interactive tools to help people play an active role in managing their own health.
www.webmd.com