Cocaine is a natural alkaloid present in the leaves of the coca plant, i.e., Erythroxylon coca, a shrub that grows well in South America, Mexico, Indonesia, and West Indies. It occurs as colourless to white crystals, or white crystalline powder. Therapeutic use is as a topical local anaesthetic for mucous membranes in the nose, eye and ear. Cocaine is an ester of benzoic acid. The major clinical effects are due to an increase in catecholamines. Tachycardia and hypertension are characteristic as is vasoconstriction in specific organ beds such as the coronary circulation. Intracerebral haemorrhage and myocardial infarction can occur and chronic use results in accelerated atherosclerosis.