We report a case of asthma that was relieved by aspirin and other cyclooxygenase inhibitors. The patient, a 51-year-old man, was admitted to our hospital because of an asthmatic attack. Onset of asthma had occurred at the age of 40 years, after a flu-like infection, and was preceded for several years by perennial rhinitis and loss of the sense of smell. The course was perennial, and unrelated to the seasons. These clinical features resembled those of aspirin-induced asthma (AIA). Therefore, suspecting AIA, we performed a aspirin-DL-lysine iv challenge test. After aspirin-DL-lysine injection, FEV1 was increased by about 30% and nasal obstruction was improved. Other cyclooxygenase inhibitors (indomethacin, mefenamic acid, ketoprofen) also improved FEV1 by more than 30%. Hydrocortisone sodium succinate (HCs) improved FEV1 about 20%. Lipoxygenase inhibitor (AA861) produced an evident attack, but continued administration did not result in complete tolerance. On the other hand, seven other AIA patients showed no reaction to AA861. DSCG had an acute bronchodilative effect similar to that of AIA. Paraben and chloramphenicol sodium succinate (CMs) produced an asthmatic attack. The present patient showed a marked improvement in response to cyclooxygenase inhibitors and HCs, in contrast to the situation in AIA, and developed an evident asthmatic attack in response to lipoxygenase inhibitor. He showed marked improvement in the response to DSCG and developed an asthmatic attack in response to paraben and CMs, as in AIA. Our results suggest an abnormality of Arachidonic acid metabolism not only in AIA but also in asthma relieved by aspirin.(ABSTRACT TRUNCATED AT 250 WORDS)