Fatigue is one of the most frequent symptoms that brings a patient to the doctor. The causes are numerous and, in fact, it can accompany almost any illness. The presence of fatigue is, however, an important indicator of serious disease. In 1979 Dr. Cuyler Hammond's report on the 20 year long Cancer Prevention Study, which surveyed over a million Americans, found that a positive answer to the question "do you fatigue easily?" was predictive of a higher death rate from disease, including cancer, than any other question!