A patient who claimed benefit from aspirin for her reversible bronchospasm was challenged orally in a placebo-controlled study with aspirin and other aspirin-like drugs. Specific airways conductance and spirometry were monitored for up to 150 minutes after oral challenge. Aspirin, mefenamic acid, and ibuprofen administration resulted in marked (45% to 80%) improvement in forced expiratory volume in 1 second (FEV1) compared to lactose placebo. Indomethacin, sodium salicylate, and tartrazine resulted in modest (15% to 25%) FEV1 improvement, while phenylbutazone produced a 25% decrease. These results are discussed here in terms of the ability of these drugs to inhibit the prostaglandin synthetase enzyme system. This case suggests that aspirin and other nonsteroidal anti-inflammatory drugs may be beneficial rather than harmful in some asthmatic patients.