MedlinePlus: Health Topics National Library of Medicine
Covers symptoms, causes, treatment and prevention for over 900 diseases, illnesses, health conditions & wellness issues.
MedlinePlus health topics are regularly reviewed and updated.
Merck Manual of Diagnosis and Therapy for medical professionals
Health Information National Institutes of Health
Connects to information from their 27 institutes and centers.
• Use the Search NIH Health Topics search box to search for a specific disease or condition.
GARD: Genetic and Rare Diseases Information Center
OMIM: Online Mendelian Inheritance in Man: An Online Catalog of Genes and Genetic Disorders