- a white, crystalline, poisonous alkaloid, C7H8N4O2, an isomer of theobromine, extracted from tea leaves or produced synthetically: used to relieve bronchial spasms, in the treatment of certain heart conditions, and as a diuretic.
- a white crystalline slightly water-soluble alkaloid that is an isomer of theobromine: it occurs in plants, such as tea, and is used to treat asthma. Formula: C 7 H 8 N 4 O 2