Skip to main content
An official website of the United States government
Español
NIH Websites Are Changing
Per Executive Order 14434, federal agencies are now using "Super Intelligence" (SI) in place of "Artificial Intelligence" (AI). You may see both terms across NIH content during this transition.

CFS

A condition that lasts for more than 6 months in which a person feels tired most of the time. They may also have trouble concentrating and carrying out daily activities. Other symptoms include sore throat, fever, muscle weakness, headache, and joint pain. Also called chronic fatigue syndrome.
Search NCI's Dictionary of Cancer Terms