BackgroundThe prevalence of cognitive disorders in hemodialysis patients is twice as high as the general population, while these disorders often are undiagnosed. Timely prevention and treatment can improve their personal and social functions. Aim of study was determined the effect of Valerian on cognitive disorders and electroencephalography (EGG) in hemodialysis patients.MethodsThis crossover, double-blind clinical trial was conducted on 39 hemodialysis patients. The patients were randomly divided into two groups. Group A (n = 19) took Valerian capsules and Group B (n = 20) received placebo capsules 60 min before bedtime for one month. The type of treatment was replaced between the two groups after a one-month wash-out. The Mini Mental State Examination (MMSE) questionnaire was completed and EGG was performed before and after intervention in both periods.ResultsThe cognitive scores of the Group valerian were increased significantly in the first (p = 0.003) and the second (p = 0.005) periods. In addition, the mean increase in the cognitive scores in the Group valerian was significant in the first (p = 0.028) and the second periods (p = 0.030). However, the changes in EGG showed no significant difference before and after intervention in two groups.ConclusionThe findings of this study indicated that valerian could be effective and significantly improve patients’ cognitive status; however, no significant changes were observed in the electroencephalography of the hemodialysis patients.Trial registrationIRCT201606076318N7–2016-06-17.