MEDLINEplus

MEDLINEplus is an online resource for consumer health information, current health topics and news, drug information, and medical dictionaries. It's a gold mine of up-to-date, quality health care information from the world’s largest medical library, the National Library of Medicine at the National Institutes of Health. MEDLINEplus is for anyone with a medical question. Both health professionals and consumers can depend on it for accurate, current, medical information. 

http://medlineplus.gov