Theobromine, a methylxanthine, is a mild stimulant that occurs naturally in many plants, such as cocoa, tea, and coffee plants.  Theobromine is the principal alkaloid found in the cocoa bean and in tea..  It is extracted from the bean husks and used in the synthesis of caffiene.  It has been used in various pharmaceuticas products.  Theobromine is consumed mostly through chocolate-based foods.  Teobromine has a mild diuretic action similar to caffeine, but stimulates the central nervous system about ten-fold less than that of caffeine.  This is not true for domestic animals, especially dogs, who metabolize theobrimine very slowly,  and are therefore, vulnerable to cardiac and central nervous system distress.