ObjectiveThis study was initiated to investigate the effect of Portulaca oleraceae on morphine dependence in mice.Materials and MethodsDependence was induced using the subcutaneous injections of morphine for 3 days. On the day 4, morphineinjected 2 h prior to intraperitoneal injection of naloxone. The plant extracts ethanolic or aqueousadministered 0.5 h before the final dose of morphine. The number of jumping during the 30 min period after naloxone injection was considered as a measure of withdrawal syndrome.ResultsBoth extracts reduced the jumping episodes dose-dependently. The maximum effect was observed at dosesof 0.28 g/kg and 1.4 g/kg for the aqueous and ethanolic extracts, respectively. Clonidine and extractsdecreased the total activity in locomotion test.ConclusionThese findings indicated that Portulacea oleraceae extracts can decrease morphine dependence in mice.