[1] Trace amounts of theophylline are naturally present in tea, coffee, chocolate, yerba maté, guarana, and kola nut.

[1][3] The name 'theophylline' derives from "Thea"—the former genus name for tea + Legacy Greek φύλλον (phúllon, "leaf") + -ine.

[11] The use of theophylline is complicated by its interaction with various drugs and by the fact that it has a narrow therapeutic window (<20 mcg/mL).

[2] Its use must be monitored by direct measurement of serum theophylline levels to avoid toxicity.

Trace amounts of theophylline are also found in guarana (Paullinia cupana) and in kola nuts.

[28] Theophylline is distributed in the extracellular fluid, in the placenta, in the mother's milk and in the central nervous system.

Clearance of the drug is decreased in these conditions: elderly, acute congestive heart failure, cirrhosis, hypothyroidism and febrile viral illnesses.

[medical citation needed] Theophylline was first extracted from tea leaves and chemically identified around 1888 by the German biologist Albrecht Kossel.

[31][32] Seven years later, a chemical synthesis starting with 1,3-dimethyluric acid was described by Emil Fischer and Lorenz Ach.