Context: Dihydrotanshinone (DHT), a natural compound from Salvia miltiorrhiza Bunge (Lamiaceae), showed higher cytotoxic potential compared with other tanshinones. Its effect and mechanism on gastric cancer have not been investigated.Objective: This study evaluates the effects of DHT on cell proliferation and apoptosis on gastric cancer cells, and elucidates its molecular mechanisms.Materials and methods: Human gastric cancer MGC803 and SGC7901 cells were treated with various concentrations of DHT (0–15 μM) for 24 and 48 h, and cell growth was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Cell apoptosis was analysed by flow cytometry and DAPI staining. Western blots were performed to investigate changes in the level of apoptosis related genes in gastric cancer cell.Results: DHT exhibited obvious inhibition of the survival of gastric cancer cells. The IC50 values in SGC7901 and MGC803 cells were 9.14 and 5.39 μM for 24 h, respectively. Cells treated with 6 μM DHT resulted in 41.3% and 35.4% apoptotic cell fractions in SGC7901 and MGC803 cells, respectively, significantly higher than that of the control. Hallmarks of apoptosis were observed in gastric cancer cells after DHT exposure. DHT enhanced the expression levels of cleaved caspase-3, caspase-9 and poly-ADP-ribose polymerases. Furthermore, DHT increased the phosphorylation of JNK and p38 in SGC7901 and MGC803 cells.Conclusion: DHT induced growth inhibition and apoptosis of gastric cancer cells, involving activation of caspase proteins and the JNK/p38 signaling pathway. The results indicated that DHT has a promising chemotherapeutic potential for human gastric cancer.