Objective To study the inhibition effects of all-trans-retinoic acid(ATRA) and arsenic trioxide(As2O3) on human hepatocarcinoma cell HepG2 in vitro and in vivo.Methods The inhibition effect of ATRA combined As2O3 on the grouth of cultured HepG2 cells was determined by MTT assay in vitro.The transplant tumor mouse model was used to observe the inhibition effects of ATRA and As2O3 on HepG2 cells in vivo.Results ATRA could inhibit the growth of cultured HepG2 cells in vitro in a dose-dependent manner.The inhib...