Timolol maleate is a new, potent ocular antihypertensive that has an effect additive with other antiglaucoma medications. It does not cause miosis and is relatively free of ocular complications, although a few have been documented. Timolol does exacerbate asthma and should not be used in patients with a history of this disease. It should be used with caution in cases of significant cardiovascular disease and may produce occasional psychic disturbances. In general, timolol is a potent, effective, and relatively safe drug with few ocular side effects but should be used with appropriate care.