Aspirin idiosyncrasy is infrequently discussed in the dental literature. The severity of the case described illustrates the importance of complete familiarity with the syndrome. Because the patient who is sensitive to the drug may not volunteer this information, the dentist must include specific questions about asthma, nasal polyps, and adverse clinical reaction to aspirin in the initial interview of the patient. Suspicion of this idiosyncrasy will result in avoidance of aspirin; this may well prevent a life-threatening reaction. Acetaminophen is a safe alternative analgesic agent for such patients.