Theobromine is a dimethylxanthine having the two methyl groups located at positions 3 and 7. A purine alkaloid derived from the cacao plant, it is found in chocolate, as well as in a number of other foods, and is a vasodilator, diuretic and heart stimulator. It has a role as an adenosine receptor antagonist, a food component, a plant metabolite, a human blood serum metabolite, a mouse metabolite, a vasodilator agent and a bronchodilator agent.