Objective:To study the inhibitory effect of protoporphyrin disodium(NAPP) on human hepatoma carcinoma cell strain of SMMC-7721 cells in vitro.Method:The maximum atoxic concentration(TC0) of NAPP was determined by drug toxicity test on normal human hepatocyte strain of QSG-7701 cells.TC0 was used as the initial concentration,five different concentrations of NAPP were diluted by 10 times gradient dilution,and applied to treat the human hepatoma carcinoma cell strain of SMMC-7721 cells cultured in vitro.MTT as...