Theophylline, also known as dimethylxanthine, is a methylxanthine drug used in therapy for respiratory diseases such as COPD and asthma under a variety of brand names. Because of its numerous side-effects, the drug is now rarely administered for clinical use. As a member of the xanthine family, it bears structural and pharmacological similarity to caffeine. It is naturally found in tea, although in trace amounts (~1 mg/L), significantly less than therapeutic doses. It is found also in cocoa beans. Amounts as high as 3.7 mg/g have been reported in Criollo cocoa beans.