Introduction:The Alzheimer Disease (AD) is the most common form of dementia that leads to memory impairment. As the oxidative stress plays an important role in AD pathogenesis, the current study aimed at examining the protective effects of Cyperus Rotundus as an antioxidant on amyloid β (Aβ)-induced memory impairment.Methods:Twenty-eight Wistar male rats received intrahippocampal (IHP) injection of the Aβ (1-40) and C. rotundus (400 mg/kg, intraperitoneally). Spatial memory was assessed by the Morris water-maze (MWM) task.Results:In the MWM, Aβ (1-40) significantly increased escape latency and traveled distance (P<0.001). The administration of C. rotundus attenuated the Aβ-induced memory impairment in the MWM task.Conclusion:The current study findings showed that C. Rotundus could improve the learning impairment, following the Aβ treatment, and it may lead to an improvement of AD-induced cognitive dysfunction.