OBJECTIVE: To study the inhibitory effect of Acanthopanax giraldii Harms Var. Hispidus Hoo polysaccharides (AGP) on SGC-7901 gastric cancer cells and its possible mechanism. METHODS: Cell doubling time analysis, colony forming assay and MTT assay were adopted to study the inhibitory effect and its characteristics. We also analyzed the amount of protein expressed by oncogenes, antioncogenes and cell factors using flow cytometric analysis. RESULTS: AGP inhibited the proliferation of SGC-7901 cells and cell colony forming ability. AGP did not inhibit the viability and function of lymphocytes of peripheral blood in healthy subjects and human embryonic tenocytes, except for the highest dosage of AGP (P