A bronchodilator found in trace amounts in tea. It is a dimethylxanthine, specifically 1,3-Dimethylxanthine, represented by the empirical formula C₇H₈N₄O₂. It is a white crystalline powder and has a water solubility of 0.1 - 0.5 g/100 mL @ 21.5° C. Generally, tea contains 3-4 milligrams of theophylline. It is also available as a prescription drug in capsule, elixir, oral solution, tablet, extended-release capsule, extended-release tablet, and syrup forms.