Breast Cancer:
Breastcancer.org
National Breast Cancer Organization
Susan G. Komen Breast Cancer Foundation

Cancer:
American Cancer Society
Association of Cancer Online Resources
CancerCare
Cure Search National Childhood Cancer Foundation Children's Oncology Group
My Cancer Place
National Cancer Institute
Oncolink
Surviving Mesothelioma
Women's Cancer Network

Children:
American Academy of Child and Adolescent Psychiatry
Juvenile Diabetes Research Foundation International
KidsHealth

Diabetes:
American Diabetes Association
National Diabetes Information Clearing House

Drugs:
Drug Information Online
RxList the International Drug Index
United States Food and Drug Administration

General:
Alzheimer's Association
Centers for Disease Control and Prevention
Clinical Trials
Family Doctor
Health Search Plus
Healthfinder
Lupus Foundation of America, Inc.
Maternal and Family Health Services, Inc.
Mayo Clinic
Medem
MedlinePlus
North American Menopause Society
Pennsylvania Department of Health
WebMD

Heart Disease:
American Heart Association
National Heart, Lung and Blood Institute

Mental Health:
American Foundation for Suicide Prevention
Anxiety Disorders Association of America
Mental Health America
National Institute of Mental Heath
National Suicide Prevention Lifeline