Objective To observe the antiangiogenesis of panaxoside-Rg3 on mice intraperitoneally implanted with ascites tlnnor cells.Methods 25 female and 25 male Kunming mice were random divided into five groups:Group I injected with normal saline (0.9%NS),Group Ⅱ with cisplatin(DDP 0.5mg/kg),Group Ⅲ,with low-dose panaxoside-Rg3(LPD 0.3mg/kg),Group Ⅳ with middle-dose panaxoside-Rg3(MPD 1.0mg/kg),Group Ⅴ with high-dose panaxoside-Rg3(HPD 3.0mg/kg).Experimental ascitic hepatocarcinoma of H22 lines model were successfully established among all groups,and 24 hours later intraperitoneal infusion of 0.2ml medicines was given to each mouse once every day for 14 days.24 hours after the over of the treatment,all mice were executed.Enzyme linked immunosorbent assay(ELISA)method was used to detectt he different VEGF level in the ascites and serum of all groups and expressions of micmvessel density (MVD)of peritoneum tumor node was calculated by immunohistochemical staining with CD31 antibody.Morphological of tumor cell in abdominal cavity and new vascular in peritoneum tumor node were observed by transmission electron microscope.Results With the increase of concentration of panaxoside-Rg3,expressions of the VEGF level of the ascites and the serum and MVD in peritoneum dropped(P＜0.05)and decreased more than that in the NS group and the DDP group(P＜0.05).Morphological changes of tumor ceHs in panaxoside-Rg3 group were observed with electronic scope,more apoptosis and necrosis cells were found.Capillary vessel basal lamina was smoothing.Condusion Panaxoside-Rg3 decreases the permeability of mierangium and inhibit the neovascula-rization of peritoneum by decreasing the VEGF level,accordingly,panaxoside-Rg3 inhibit the formation of malignant ascites.This would offer foundation of theory for clinical application.