Eccrine sweat is produced by millions of miniscule glands buried in the skin. Eccrine sweating from the general body surface is an extremely important function in human thermoregulation; disturbances either in the control of sweating activity or in the glands themselves can result in problems ranging from minor social embarrassment to fatal hyperpyrexia. A general review of the function and control of normal sweating precedes an overview of sweating abnormalities.