Chronic Fatigue Syndrome | Overview


What is chronic fatigue syndrome?

Chronic fatigue syndrome (CFS) is a disease that causes you to become so fatigued (tired) you can't perform normal daily tasks. This is called chronic fatigue. The main symptom of CFS is chronic fatigue that lasts more than 6 months. Physical or mental activities often make the symptoms worse, and rest usually doesn't improve the symptoms.

Written by editorial staff

Reviewed/Updated: 02/14
Created: 01/94