A recent study showned that complementary medicine is gradually gaining wide acceptance. In the present study, the herbal mixture extract (H3) composed of 3 oriental herbal plants was investigated for anticancer activity in vitro and in vivo. H3 inhibited PANC1 cell growth by promoting G0/G1 arrest (11% increase) and apoptotic cell death (9% increase). H3 also suppressed stem cell-like side population cells (4% decrease) and migration activity (24% decrease). In contrast, gemcitabine decreased side population cells and migration activity by 3 and 11%, respectively. These effects of H3 and gemcitabine were further studied by examining the expression of apoptosis-associated genes (CXCR4, JAK2 and XIAP) and stem cell-associated genes (ABCG2, POU5F1 and SOX2). We also found that H3 suppressed tumor growth by 46% in a PANC1‑xenograft model, while gemcitabine caused a 36% decrease. The antitumor effects of H3 were confirmed by western blot analysis for COX-2 and cytochrome c expression. Furthermore, necrotic cell death and erythrocyte-containing cavities were detected in tumor tissue by hematoxylin and eosin (H&E) staining. Notably, the combinatorial therapy (H3 and gemcitabine) increased tumor growth compared to that in the control. In conclusion, the present study shows that H3 has promise as a therapeutic agent against pancreatic cancer and its cancer stem cells.