AIM: To explore the molecular mechanisms of action of paclitaxel and NM-3 on human gastric cancer in severe combined immune deficiency (SCID) mice.METHODS: Human gastric cancer cells SGC-7901 were implanted into SCID mice and mice were treated with paclitaxel and NM-3. The effects of paclitaxel and NM-3 on apoptosis of human gastric cancer cells were analyzed using flow cytometry, TUNEL assays, and DNA fragment analyses.RESULTS: Apoptosis of SGC-7901 cells was successfully induced by paclitaxel, NM-3, and the combination of paclitaxel and NM-3 24 h after injection as shown by the presence of apoptotic hypodiploid peaks on the flow cytometer before G1-S and a characteristic apoptotic band patt in the DNA electrophoresis. The apoptotic rate detected by TUNEL assay was found to be significantly higher in the paclitaxel/NM-3 compared to the control group (38.5% ± 5.14% vs 13.2% ± 1.75%,P ＜ 0.01).CONCLUSION: Paclitaxel in combination with NM-3 is able to induce apoptosis of the human gastric cancer cells in SCID mice effectively and synergistically.