Also known as CFS, this is a is a long-lasting illness that affects the brain and many parts of the body.

It is related to other diseases such as fibromyalgia and myalgic encephalomyelitis (ME). The cause is unknown, and many treatments have been tried.

All sites submitted to this category must be designed for use by kids / teens and provide information on or about heart disease.

Websites designed for parents or teachers, or to sell products or services, will not be accepted.

English-only sites. Sites in other languages should be submitted to the appropriate category in /International.