The anti-allergic action of amlexanox is reported to be associated with inhibition of the release of LTC4, LTD4 and histamine, and with antagonistic activity on leukotrienes. The patient was a 18-year-old female who had suffered from bronchial asthma since the age of fifteen. We diagnosed the case as aspirin sensitive asthma because of development of a severe asthmatic attack with syncope after oral administration of an analgesic for treatment of a common cold at the age of seventeen. She also had sensitivity to toothpaste. Three-minute aerosol inhalation challenge with 0.1, 1 and 10% solution of sulpyrine was performed as a stepwise increment at 20 minutes intervals. This inhalation test was positive and it evoked simultaneous increases of LTC4, LTD4 and histamine in the peripheral blood. Since the commencement of oral administration of 150 mg per day of amlexanox, the patient has had no attacks for about 8 months. In the second inhalation test, premedication with amlexanox elevated the threshold of sulpyrine and inhibited the release of LTC4, LTD4 and histamine. We report that amlexanox was of use to control asthmatic attacks in this aspirin-sensitive asthmatic patient.