The Mayo Clinic
The Mayo Clinic is an internationally recognized academic medical center in Rochester, Minnesota. The website provides a wealth of medical information and keeps advertising content separate and well-marked.
Medline Plus is a completely non-commercial website with a variety of references for the layperson including tutorials on common medical topics, a medical dictionary, a medical encyclopedia, drug references, links to ongoing clinical trials, and more.
Up To Date
Up to Date is an evidence-based resource for physicians publishing in-depth articles for patients about hundreds of medical conditions.
The websites noted above maintain strict standards regarding editorial and advertising content and corporate sponsorship.