Cuminum is a one-year grass-like plant that has been used in traditional medicine for treatment of diarrhea, toothache and epilepsy. Too many animal model studies have shown the effects of the essential oil of this plant on epilepsy singes and on morphine withdrawal syndrome too. In this experiment, 48 male mice received 100 mg/kg ephedrine for 4 days and in 5th day they received cuminum in a dose dependent manner (0.1, 0.5, 1, 2%, 5 ml/kg, i.p).The mice were placed individually in a square Plexiglas's chamber after sixty minutes and then the amount of their loco motor activities were recorded for 5 minutes (Expression). In a series of parallel experiences further 48 mice received the oil in a dose dependent manner exactly 60 minutes before receiving ephedrine during four days of protocol (Acquisition). In the fifth day the amount of loco- motor activities of each mouse was recorded for 5 minutes. The results of findings analysis showed that consumption of cuminum can significantly decrease loco motor activities in both groups (acquisition and expression) in comparison with control groups that used Tween 80 as a transitionalphase and saline. Findings showed that we can use cumin oil as amedicinal plant for prevention and treatment of bipolar disorders hopefully. But approving of these results needs more researches on human being.