Objective: In this study, we assessed the laxative effects of Prunus amygdalus oil (PAO) in constipation model of mice. Method: The animals were divided into 6 groups and Prunus amygdalus oil was orally administered in two dose-strengths (3.0 ml/kg/day and 6.0 ml/kg/day) in mice. Group one was administered with Lactulose (30 ml/kg/day) as standard. Understandings of the possible mechanism of laxative action 2 groups of animals were pretreated with atropine (10 ml/kg/day) that moderately inhibit the laxative activity of Prunus amygdalus oil. Results: Results of our study revealed that treatment of PAO was effective in increasing the fecal number and fecal weight and this increase was very close to standard drug Lactulose, which indicate the laxative activity of oil. Those groups of animals which were previously administered with atropine partially inhibit the laxative activity of Prunus amygdalus oil, specifying that laxative action is mainly facilitated through muscarinic receptors activation and indicated the occurrence of Acetylcholine like component. Conclusion: Our study results revealed the laxative activity of PAO mediated mainly with the cholinergic pathway. This study provides a basis for beneficial use of Prunus amygdalus oil in constipation.