The effect of an aqueous extract of the dried immature fruit of Poncirus trifoliata Raf. (Rutaceae) (PF-W) on gastrointestinal (GI) motor function was investigated by measuring the intestinal transit rate (ITR) of Evans blue in rats and mice with experimental GI motility dysfunctions (GMDs). GMD was induced by appropriate surgery or by the administration of acetic acid, atropine, L-DOPA, or morphine to the animals. The ITR in these GMD animals was significantly retarded compared to normal animals. The retardation, however, was significantly inhibited by the intragastric administration of PF-W (0.1-1g/kg) in a dose dependent manner for all GMD models except for L-DOPA-induced GMD. The above results suggest that PF-W has the potential for development as a prokinetic agent that may prevent or alleviate GMD in human patients.