AIM To observe the influence of Mongolian traditional medicine DAGEBU-15 (MD-15) to the contraction effects of isolated intestinal smooth muscle of rat caused by acetylcholine(ACh).METHODS Isolated intestinal perfusion method was used to record the rat intestinal muscle tension by JH-type 2 and BL-420 biological function system.Krebs perfusion fluid with gas mixture of 95% O2 and 5% CO2, temperature is (37 ± 1) ℃.The semilogarithmic molar concentration cumulative administered method was used.Administering in proper order according to the following sequence of concentration of ACh without or with MD-15, the concentration of MD-15 was 1 mg·L-1 and 10 mg·L-1.The ACh concentrations of Magnus bath were 1 × 10-7 mol· L-1, 1 × 10-6 mol· L-1,1 × 10-5 mol·L-1, 1 × 10-4 mol· L-1 and 1 × 10-3 mol· L-1, respectively.Observed and recorded the changes in contraction after administering.The solution need not be changed each administration.After the contraction of intestinal smooth muscle is stable, add the next concentration ACh.The largest percentage of contraction effect caused by ACh was y-coordinate, the logarithm molar concentration of ACh (-lg[D]) was as abscissa and drew dose-response curves.RESULTS MD-15 of each dose group make the cumulative dose-response curve of ACh shifted to the right and the maximum responses were reduced.MD-15 was an non-competitive antagonist of ACh.The maximum responses caused by ACh with 1 and 10 mg· L-1 MD-15 was (81.74 ± 11.22)% and (75.90 ± 16.79)% of the maximum responses caused by ACh without MD-15, respectively.CONCLUSION MD-15 can inhibit the contraction effect of small intestinal smooth muscle of rats.