Acai berry is a kind of blackberry and grows in Africa. It’s claimed that it contains high amount of antioxidants, provides slimming, and gives energy. It has become a popular herbal product recently. In literature psychosis and mania cases associated with the use of herbal products were reported. This case is a psychotic mania seen after the use of a slimming pill that contains acai berry. A 19 year-old, male, student was admitted to the hospital 3 months before. Patient begun to use slimming pill which contain acai berry. After starting the use of this slimming pill, insomnia began and he started feeling himself energized. In the last one week, psychotic mania appeared. There was no organic pathology. Haloperidol 40 mg/day was applied and complete remission was achieved in 15 days. He was discharged with low dose haloperidol treatment. There is an uncontrolled use of herbal products especially acai berry, which is popular in recent years. So psychosis and mania cases are increasing. During psychiatric examination, it must be considered using herbal products which is claimed completely natural and have no side effects but not actually.