OBJECTIVE: To study the mechanism of the inhibitory effect of ginsenoside Rg3 on colon cancer cell migration.METHODS: Transwell migration assays were performed to investigate the inhibitory effect of ginsenoside Rg3 on SW480 cell migration. Electrophoretic mobility shift assays(EMSAs) and dual luciferase reporter assays were used to study the suppression capability of Rg3 on nuclear factor kappa B(NF-κB) activity. Western blotting was adopted to determine protein levels.RESULTS: Two-hundred micromolar ginsenoside Rg3 significantly inhibited SW480 cell migration(P < 0.05). EMSA showed that Rg3 suppressed the DNA binding ability of NF-κB. Dual luciferase reporter assay showed that Rg3 decreased NF-κB-regulated gene transcription(P < 0.01). Western blots indicated that Rg3 down-regulated expression of the NF-κB-regulated matrix metalloproteinase 9,cyclooxygenase-2 and C-Myc. An NF-κB inhibitor,pyrrolidine dithiocarbamate,enhanced the inhibitory effect of Rg3 on SW480 cell migration.CONCLUSION: Ginsenoside Rg3 has a strong antitumor migration capability by suppressing NF-κB activity and expression of NF-κB-regulated gene products. It could be a good adjuvant for colon cancer patients during the course of chemotherapy.