Background & Aims: Bunium persicum Boiss. Belongs to Apiaceae family and its fruit contains high level of essential oils used as native medicinal plant in traditional medicine. Methods: The essential oil of Bunium persicum (EOBP) was extracted by Clevenger apparatus using hydrodistillation. Lethal dose, 50% (LD50) was calculated based on Lorke’s method. Effects of EOBP (20- 80 mg/kg) on upper gastrointestinal transit and on castor oil-induced diarrhea were investigated in adult Wistar rats weighting 200-220 g of eithersex. Results: The LD50 was determined as 375 mg/kg. Abnormal behavioural activities included lethargy, weakness, recumbence, and slow and shallow respiration. EOBP (20 mg/kg)showed inhibitory effects more than atropine where high doses (40 mg/kg) had same inhibition in contrast with atropine. EOBP inhibited intestinal motility more than atropine at lower doses. EOBP inhibitory effect was enhanced with atropine insignificantly. The EOBP (20 and 80 mg/kg) also caused a dose-dependent decrease of diarrheal parameters and markedly protected rats against castor oil-induced diarrhea. The maximal effect of the EOBP wassimilar to loperamide, one of the most efficacious and widely employed antidiarrheal drugs at the present time. Conclusion: These primary data indicated that the plant may contain some biologically active constituents that may reveal antimotility and antidiarrheal effects and support the popular therapeutic use of Bunium persicum in traditional medicine for gastrointestinal disorders