There is evidence that aspirin is partially effective in the prophylaxis of various vasoocclusive disorders. This article reviews pharmacologic opportunities for improvement over and above the therapeutic effect of aspirin. It is concluded that several rational possibilities merit consideration, in particular, the use of combinations of drugs that affect the thrombotic process at different points. ABSTRACT There is evidence that aspirin is partially effective in the prophylaxis of various vasoocclusive disorders. This article reviews pharmacologic opportunities for improvement over and above the therapeutic effect of aspirin. It is concluded that several rational possibilities merit consideration, in particular, the use of combinations of drugs that affect the thrombotic process at different points. Such strategies will ultimately require validation by clinical trial.