Theobromine, also known as xantheose, is the principal alkaloid found in Theobroma cacao (the cacao plant). It is slightly water-soluble with a bitter taste. You can find theobromine in chocolate, as well as in other foods like tea ( Camellia sinensis ), some American hollies (yaupon and guayusa), and the kola nut. Although it is a white or colorless solid, commercial samples can sometimes appear yellowish.