Abstract: Curcumol is the antitumor constituent of the plant, Curcuma Wenyujin To study the effects of curcumol and sodium phosphorylcureumol （CP-Na） on the membrane of Ehrlich ascites tumor cells, fluoresent probe dis-C₃-（5） and atomic absorption spectrum techniques were used respectively to measure the changes in membrane potentied and membrane permeability to potassium ions. The intensity of fluorescence increases after addition of curcumol and CP-Na to suspension of tumor cells. The intensity of fluorescence was calibrated by means of potassium diffusion potential induced by valinomycin. By these methods the change of membrane potential can be calculated, for curcumol and CP-Na mem- brane potential of tumor cells was deporlarigzed about 52mV a and 35mV. The intracellular potassium ion concentration of tumor cells decreases after adding the curcumol and CP-Na, and potassium ion coucentration Within the medium increases. The mechanisms of those changes mentioned above were cliscussea.

Key words: curcumol, antitumor agent, cell membrane potential, Ehrlich ascites tumor