Aspirin: benefit and risk in thromboprophylaxis.

Aspirin is often perceived either as a harmless panacea or as a useless poison which causes endless, needless trouble. We have carefully reviewed the literature on all aspects of aspirin and find that neither view is justified. Regular use of even low-dose aspirin (150 mg/day or less) may lead to clinically-important adverse events, particularly haemorrhage. The risk of such an event is considerably outweighed by the benefit for patients with a significant risk of a thromboembolic event. For individuals without a clear risk of thrombosis or thromboembolism, the balance is more even: indiscriminate aspirin-taking is to be discouraged.