Dementia with Lewy bodies (DLB) has been associated with important behavioural disturbances, such as psychotic symptoms. Unfortunately, neuroleptic sensitivity in these patients limits eective pharmacological management of these symptoms. Seven patients, ®ve male and two female (mean age 75.3+4.7 years, range 68±81), diagnosed with DLB were treated with the acetylcholinesterase inhibitor donepezil (5±10 mg once daily) to determine its eect on treating behavioural disorders. Although the intended length of treatment was a minimum of 8 weeks, only three patients completed 8 weeks of therapy, one patient completed 6 weeks, two patients completed 4 weeks and one patient was discontinued after 5 days. The primary outcome (behavioural disturbances) was measured prospectively by the Neuropsychiatric Inventory (NPI), while other outcomes included cognition (Mini-Mental State Examination (MMSE)) and Clinical Global Impression. Three of the seven subjects showed marked improvement in behaviour, with NPI scores dropping signi®cantly over time. Donepezil therapy was discontinued prematurely in three of the cases due to insucient response and/or adverse events. Overall, ®ve of the seven patients were rated at least minimally improved in behavioural symptoms. Our experience with donepezil in this group of patients shows promise. Given the limited experience with this agent in treating behavioural disorders associated with DLB, further studies are warranted.