Timolol ((S)-L-714,465; MK 950) hemimaleate is a β-blocker available for both topical and systemic administration. Topical Timolol hemimaleate is primarily used to reduce intraocular pressure with open-angle glaucoma and ocular hypertension. Timolol hemimaleate can also be used for the research of infantile hemangiomas, hypertension, myocardial infarction, migraine prophylaxis, and atrial fibrillation.Timolol also has cardioprotective effect.