Information about many types of rare diseases and disorders, including causes, symptoms, diagnosis and treatment, including orphan drugs. Site also offers news about rare diseases, orphan drugs, and clinical trials.

The eMedicine point-of-care clinical reference features up-to-date, searchable, peer-reviewed medical articles organized in specialty-focused textbooks, and is continuously updated with practice-changing evidence culled daily from the medical literature.

A large collection of information on health and behavior problems relating to dog and cats.

HealthCentral.com is one of the most trusted sources of medical information and up to date news and contains a doctor-approved health encyclopedia of diseases and conditions, the ability to find symptoms and treatments. Also drug information with side effects and interactions

The leading source for trustworthy and timely health and medical news and information. Providing credible health information, supportive community, and educational services by blending award-winning expertise in content, community services, expert commentary, and medical review.

Comprehensive dictionary of medical eponyms. The stories of diseases, conditions, medical syndromes and the people whose names they carry.

CIGNA is a global health service company, dedicated to helping people improve their health, well-being and security. We provide an integrated suite of health, life, accident, disability and other wellness benefits to groups and individuals, serving over 45 million people throughout the United States and around the world

Extensive knowledge base of medical information on symptoms, diagnosis, and misdiagnosis of more than 20,000 medical conditions. Research causes of your symptoms or research treatments for diseases.