Some patients with imperative cardiologic indications for combination therapy with aspirin and clopidogrel (stent placement and/or acute coronary syndrome) have a history of allergy to aspirin. In other patients, symptoms of aspirin hypersensitivity may develop in the days after stenting, at which time discontinuation of aspirin carries a risk of catastrophic stent thrombosis. We challenged 16 such patients using rapidly escalating low doses of aspirin. In 14 patients, reintroduction was immediately successful, and 11 underwent uneventful stent placement. Two patients developed transient allergic reactions, 1 of whom was successfully rechallenged 48 hours later. No late allergic reactions or adverse cardiac events were seen after a mean follow-up of 14 months. A rapid challenge-desensitization procedure may allow introduction of aspirin at therapeutic doses within a few hours.