Three different methods of anaesthesia (propofol or isoflurane with fentanyl/alfentanil, atracurium and O2/air or neurolept-anaesthesia with fentanyl, dehydrobenzperidol, pancuronium and N2O/O2) were compared in 64 patients undergoing cardiac surgery before the start of extracorporeal circulation. Plasma catecholamine contents were determined and haemodynamic changes were recorded for the detection and quantification of sympathoadrenal responses to the typical points of stimulation (intubation, skin incision, sternotomy). The level of anaesthesia was held comparable by EEG monitoring (spectral edge frequencies between 8 and 12 Hz). Noradrenaline and adrenaline showed significantly lower values in the propofol group in comparison to the groups with isoflurane and neuroleptanaesthesia. The clearest increases in catecholamines were found in all groups before starting the extracorporeal circulation. There is no evident congruity between catecholamine levels and haemodynamic changes because of various interindividual differences. Derived values of haemodynamic parameters (integrals of blood pressure, rate pressure product and triple index) are more useful than single measurements for the description of circulatory reactions.