Our previous investigations have shown that leukotrienes are important mediators/modulators in local response of the lungs to the blast injury. The aim of the present study was to investigate the effects of diethylcarbamazine (DEC), an 5-lipoxygenase inhibitor, on the acid-base balance following pulmonary blast injury. The experiments were performed on rabbits (n = 16) subjected to focused blast over-pressure on the middle thoracic region. Immediately prior to blast injury one group was treated with DEC (50 mg/kg, i.v.), and the other with the same volume of saline. Parameters of acid-base balance were measured in arterial and venous blood before and 30 minutes after injury. Obtained results indicated that DEC treatment reduced some disturbances induced by blast injury (prevents edema formation in the lungs, permits respiratory compensation of metabolic acidosis in general circulation, normalization of respirations and slightly improves the oxygen saturation of hemoglobin), in spite of intensified hemodynamic insufficiencies associated with increased hypotension and acidosis in the peripheral circulation.