Theobromine, also known as xantheose, which also includes the similar compounds theophylline and caffeine. with the suffix -ine given to alkaloids and other basic nitrogen-containing compounds.

Theobromine is a water insoluble, crystalline, bitter powder; the colour has been listed as either white or colourless. It has a similar, but lesser, effect to caffeine, making it a lesser homologue. Theobromine is an isomer of theophylline as well as paraxanthine. Theobromine is categorized as a dimethyl xanthine, which means it is a xanthine with two methyl groups.

Theobromine was first isolated from the seeds of the cacao tree in 1878 and then shortly afterwards was synthesized from xanthine by Hermann Emil Fischer.