大鼠于妊娠第7～9d,每天皮下注射dl-15甲基前列腺素F_2α甲酯(PG05)0.5mg/kg或每天口服盐酸苯乙哌啶(R1132)50mg/kg,皆有明显的抗早孕作用。皮下注射PG050.2mg/kg或单独口服R1132 10mg/kg均无抗早孕作用,妊娠第10d,血清孕酮水平下降也不明显。合并应用上述无抗 早孕作用剂量的PG05和R1132,可使抗早孕作用达100％,血清孕酮水平下降,同对照,单用PG05或R1132组比较皆有明显差异,说明两药抗早孕有协同作用。R1132又能拮抗PG05引起的小鼠腹泻和肠蠕动. Rats in pregnancy 7 ~ 9d, daily subcutaneous injection of dl-15 methyl prostaglandin F_2α methyl ester (PG05) 0.5mg / kg or oral diphenoxylate hydrochloride (R1132) 50mg / kg, are significantly anti-pregnancy effect. Subcutaneous injection of PG050.2mg / kg or oral administration of R1132 10mg / kg were no anti-early pregnancy effect, the first 10 days of pregnancy, serum progesterone levels did not decline significantly. The combination of PG05 and R1132 with no anti-gestational dose mentioned above could make anti-early pregnancy effect reach 100% and serum progesterone level decrease, which is obviously different from the control group and PG05 or R1132 group alone effect. R1132 antagonizes PG05-induced mouse diarrhea and bowel movements.