To elucidate the immunomodulatory mechanism of phenylethanoid glycosides from the seeds of Plantago asiatica by testing its effects on the maturing of murine bone marrow derived dendritic cells (DCs).Monocytes generated from bone marrow of Balb/cj mouse were cultured for 6 days in complete RPMI 1640 medium containing 10% FBS, rmGM-CSF and rmIL-4.50 mg x L(-1) acteoside or isoacteoside was added to cells on day 6 of culture for 24 h. The surface molecules expression level of DCs and their phagocytose ability were analysis by flow cytometry.Both acteoside and isoacteoside could increase the expression of CD11c, CD86, MHC II and CD80 on DCs surface. The ability of unstimulated DCs to uptake FITC-dextran was higher than that of phenylethanoid glycosides or LPS treated DCs.Both acteoside and isoacteoside could induce maturation of murine dendritic cells.