Theobromine, also known as Xantheose, is a naturally occurring alkaloid, the primary one found in the cacao plant (Theobroma cacao). It appears as a white or colorless solid, although commercial samples might have a yellowish tint. With a slightly bitter taste, theobromine has a low solubility in water (330 mg/L). Industrially, it serves as an additive and a precursor in some cosmetic products. Besides chocolate, theobromine is present in other foods like tea leaves and kola nuts.

The CAS Number of Theobromine is 83-67-0 and Theobromine is used as a vasodilator (a blood vessel widener), as an aid in urination, and as a heart stimulant.