Previously, we showed that the herbal extract EYK (Epimedium koreanum Nakai) can regulate the immune response. Other studies showed that EYK has beneficial effects in human lung cancer, angiogenesis and Alzheimer's disease (AD). However, it remains unknown whether EYK can affect cancer cell migration and invasion in human brain cancer cell lines. In the present study, we found that pre- or post-treatment with EYK inhibited phorbol 12-myristate 13-acetate (PMA)-induced cancer cell migration and invasion in A172 cells, but not in U373MG or T98G cells. Additionally, pre- or post-treatment with PMA followed by EYK decreased MMP-9 activity in A172 cells. Moreover, treatment with a NF-κB inhibitor significantly decreased cell migration in A172 cells pre- or post-treated with EYK and PMA, suggesting that EYK requires NF-κB to alter cancer cell migration. Either pre- or post-treatment with EYK significantly decreased NF-κB nuclear translocation in comparison with PMA treatment. Taken together, our results suggest that EYK suppresses PMA-induced cancer cell migration in monomorphic malignant human glioma cells by downregulating the NF-κB pathway and decreasing MMP-9 activity.