As a fundamentel experiment of the anticancer drugs, COPP, we have investigated on the influence of COPP on the growth of cultured cells and drug resistance. Mercury-hematoporphyrin was also studied as a control agent. For the estimation of the cell number, the unstained cell count method by means of 0.5% Eosin-P.B.S. was used. At the same time, the reduction ability of the succinic dehydrogenase in KB cells against T.T.C. (Triphenyl Tetrazolium Chloride) as an indicator was measured. The results obtained were as follows : when the anticancer drugs were applied to KB cells, the drugs used were effective in the high concentration, but in the low concentration, on the contrary, the drugs might stimulate the cells and cell growth appeared to be promoted, also KB cells seemed to be acquired the drug resistance following treatments with COPP 5-6 times.
