The impedance-cardiography renders possible the recognition of central haemodynamic parameters on an unbloody way. For the judgment of the method 18 female patients with hyperthyreosis were examined before and during the thyreostatic treatment. At the same time the systolic time intervals were estimated and the results from the two methods were compared. Apart from the abbreviation of PEP and the decrease of the contractility index PEP/LVET the increase of the cardiac index and the reduction of the resistance index indicate the thyreotoxic effect on the cardiovascular system.