OBJECTIVE:To study the effect of quercetin on the proliferation and apoptosis of human gastric carcinoma cell line MGC-803.METHODS:MTT assay was adopted to measure the effect of quercetin at different concentrations on the proliferation of MGC-803 cells.Cell apoptosis index(AI)induced by quercetin was measured by TUNEL assay.RESULTS: Quercetin at a certain concentration from 40?mol/L to 100?mol/L could successfully inhibit the proliferation of MGC-803 cells in a dose-dependent manner.TUNEL assay indicated that apoptosis cells induced by quercetin in treatment group were much more than that in control group after 48 hours(P