Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Reye's Syndrome

What Is It?

Reye's syndrome is a very rare disorder that damages many parts of the body, especially the brain and the liver. For unknown reasons, the parts of the cells that make energy (mitochondria) stop working correctly, causing severe illness. The most serious problems are swelling of the brain and problems with the breakdown of fat, which causes it to build up in the liver and other organs. The illness can be fatal, especially if not detected early and treated appropriately.

Although Reye's syndrome can occur at any age, it most often affects children between the ages of 3 and 12.

Reye's syndrome typically occurs several days after the child is recovering from a viral infection, such as the flu, common cold, or chickenpox. It also can develop while the child is still sick, a few days after the viral illness began. While the exact cause of Reye's syndrome is not known, researchers believe that it sometimes is caused by an abnormal response to aspirin or related products taken during a viral illness. For this reason, never give aspirin or aspirin-containing medicines to children with fever or a flu-like illness.