An experimental comparative study on isolated guinea pig-lungs has been undertaken to determine the probable beneficial effects of adding taurine to pulmonary reperfusion solutions in lung ischemia-reperfusion. 20 guinea pigs were used. The isolated lungs (n = 10 in each group) previously being perfused by oxygenated Krebs-Henseleit solution were put in normothermic ischemic conditions. After 3 hours of normothermic ischemia the lungs were reperfused (with Krebs-Henseleit solution in the control group, Krebs-Henseleit solution plus taurine 10(-2) M in the experiment group) for 20 minutes. Pulmonary artery pressures, tissue malondialdehyde (MDA) and glutathione (GSH) levels were measured before and after the ischemic period and also at the end of reperfusion. Malondialdehyde and glutathione levels of the pefusate were measured before ischemic period and at the end of reperfusion. An electron microscopic analysis was performed on the lung tissues before and after the ischemic period and also at the end of reperfusion. Decreased pulmonary artery pressure, tissue perfusate MDA levels and increased perfusate GSH levels were observed in taurine added group. Electron microscopic evaluation supported our findings indicating preservation of lamellar bodies of type II pneumocytes. It is concluded that taurine may play an important role in protecting tissue against ischemia-reperfusion injury by functioning as an antioxidant.