Platelet activation was enhanced one and three months after CABG. ASA 160 mg OD and 75 mg BID most effectively suppressed thromboxane production. Platelet aggregation was least effectively inhibited by ASA 75 mg OD. ASA higher than 75 mg OD should be considered the first 3 months after CABG. Twice daily dosing of ASA is of interest for further evaluation.