Materials and Methods: In this double blind controlled clinical trial, 85 pregnant women who referrers to the health care center were enrolled. They were randomly assigned to receive 28 sachets of 5gr sisymbrium (to use from 37^th week of pregnancy) or no treatment. The data gathered using a questionnaire which was completed by trained midwives.

Results: There was no significant difference between the intervention group and control group in the spontaneous beginning of their pains (p=0.29), but the induction of labor, the doctor's introduction for induction (p=0.043), cesarean rate (p=0.032) were higher in the non-intervention group. Whereas the Bishop's score (p=0.003), dilatation (p=0.00) and cervix effacement (p=0.008) were higher in intervention group.

Conclusion: This study showed that the probable effects of sisymbrium in the parturition process increase the probability of vaginal delivery. Since there is no contraindication for sisymbrium use during pregnancy, it is recommended that the pregnant women consume it in order to facilitate labor.