A group of naturally occurring agents present in caffeine, theophylline, and theobromine. They act on the central nervous system, stimulate the myocardium, relax smooth muscle, and promote diuresis. A commonly prescribed methylxanthine is theophylline, which is used primarily to treat asthma and chronic obstructive pulmonary disease.
Substance found in caffeine that may cause symptoms of fibrocystic breast disease in the body.