The influence of 3 different, preoperatively given glucocorticoids (30 mg/kg bw methylprednisolone, 3 mg/kg bw dexamethasone, 30 mg/kg hydrocortisone) on extravascular lung water (EVLW) was investigated in a randomised study consisting of 60 patients undergoing elective aortocoronary bypass surgery and compared to a control group having received 0.9% NaCl as placebo. EVLW-measurements were performed by using the double indicator dilution technique with indocyanine green and a microprocessed lung water computer. Besides EVLW-measurements haemodynamics and various laboratory data were studied before as well as after (15 min, 45 min, 5 h) extracorporeal circulation (ECC). ECC was followed by an increase in EVLW, which was less pronounced in the dexamethasone-group without being statistically significant (p = 0.1), however. Pulmonary gas exchange, too, did not differ statistically, in spite of a less pronounced (p = 0.1) deterioration of paO2 in the dexamethasone-group. Haemodynamics and laboratory data in the corticoid-group did not show any significant difference compared to the non-treated control group. It was concluded, that pretreatment with corticoids in pharmacological doses in cardiac surgery had no beneficial effects on extravascular lung water and pulmonary function.