1. Macroscopically normal human lung tissue was obtained from operative specimens removed for lung cancer and challenged with antigen or calcium ionophore. The release of histamine and slow-reacting substances was measured by fluorimetric and bioassay techniques respectively.
2. Benoxaprofen, a drug with inhibitory effects on the lipoxygenase and cyclo-oxygenase pathways, caused a dose-related reduction of release of slow-reacting substances without affecting histamine release.
3. These results with human lung tissue in vitro suggest that benoxaprofen may be used to investigate the role of slow-reacting substances in experimental and clinical asthma.