The pulmonary delayed-type hypersensitivity (DTH) reaction induced by picryl chloride is characterized by enhanced albumin concentration in the airway tissue in the early phase (2 h after challenge with picryl sulphonic acid). During the later phase (48 h after the challenge) enhanced tracheal reactivity to carbachol in vitro and cellular (mononuclear and polymorphonuclear leukocytes) accumulation into the airway tissue in vivo are prominent features. In this present study, the effects of a novel drug, LCB 2183, were examined in the pulmonary DTH reaction. LCB 2183 (25 mg/kg twice daily intragastric gavage) failed to inhibit the enhanced albumin accumulation in the early phase of this response. In contrast, LCB 2183 abolished the tracheal hyperreactivity and the leukocyte accumulation in the airways of picryl chloride-sensitized mice 48 h after the challenge. These results demonstrate that LCB 2183 could be effective in the treatment of airway hyperreactivity and pulmonary inflammation.