Recently it was reported that sclerosing agents frequently used for sclerotherapy of bleeding oesophageal varices can cause severe lung injury, resembling that of the adult respiratory distress syndrome (ARDS), if given intravenously to sheep. The aim of the present series was to study if steroids or aspirin given before injection of the sclerosing agent would modify or prevent the lung injury. Twenty-one sheep were randomly given either normal saline (S, 20 ml i.v., n = 8), methyl prednisolone (MP, 40 mg/kg bwt i.v., n = 6) or aspirin (ASP, 10 mg/kg bwt i.v., n = 7) 20 min before ethanolamine oleate 5% 5 ml i.v. was given. After injection of the sclerosing agent the untreated animals (S) developed a high pulmonary artery pressure (PAP) while the respiratory compliance (CT), arterial oxygen tension (PaO2) as well as the platelet (PC) and white cell counts (WBC) decreased significantly. In group MP the pulmonary changes were less severe (CT, PaO2) and the drop in PC as well as WBC was less pronounced, but the PAP increased just as much as in the controls (S). In the aspirin treated group (ASP), however, no pulmonary or circulatory changes were observed. PAP, PaO2, CT, PC and WBC remained virtually unchanged throughout the study. At post mortem the lungs of the control animals appeared moderately congested and the wet/dry weight ratio was significantly increased compared with group ASP. It was concluded that methyl prednisolone slightly attenuates acute lung injury observed after i.v. injection of the sclerosing agent ethanolamine oleate. Aspirin, on the other hand, appears to prevent this injury almost entirely.