- 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 2See also xanthine (def. 2)
- A colorless crystalline alkaloid derived from tea leaves or made synthetically, used as a cardiac stimulant and diuretic.
- A colorless, crystalline alkaloid derived from tea leaves or made synthetically. It is used in medicine especially as a bronchial dilator. Theophylline is a xanthine that is similar in structure to caffeine and is a structural isomer of theobromine. Chemical formula: C7H8N4O2.