Background: Postpartum hemorrhage (PPH) is a leading cause of mortality and morbidity worldwide. Anethum graveolens (dill) is one of the recommended herbs to reduce bleeding. Objectives: This study aimed to evaluate the efficacy of rectal suppository of Anethum graveolens on the postpartum hemorrhage (PPH). Methods: Following a randomized clinical design, 70 eligible pregnant women admitted for vaginal delivery to Umm-al-Banin Hospital in Mashhad (Iran) in 2018 were recruited in this trial. Subjects were selected by available method and randomly assigned into two groups of intervention and control. Both groups, immediately after the delivery, received routine hospital interventions. Instantly after the expulsion of the placenta, the intervention group received the first dose of rectal suppository and the subsequent doses up to five doses at intervals of 30 min. PPH was measured by weighing the blood bags and pads for 4h after labor. Data were collected using a sample selection checklist, demographic and pregnancy information forms, birth, infant, and placenta information forms, and partograph sheets. Data were analyzed by SPSS version 22 using an independent t-test or the Mann-Whitney test. Results: The two groups were homogeneous in terms of mediating variables. The mean bleeding rate at the end of the first fourth after delivery was 306.2 ± 11.2 cc in the control group and 282.4 ± 9.6 cc in the intervention group. Therefore, there was a statistically significant difference concerning post-delivery bleeding between the two groups (P = 0.001). Conclusions: Based on the findings, the rectal suppository of Anethum graveolens could effectively reduce the PPH without any adverse effects. Therefore, this efficient herbal approach is suggested to overcome the PPH.