Behavioral and psychological symptoms of dementia (BPSD) are defined as abnormal perception, thought, emotion and behaviors in patients with dementia. BPSD produce significant distress in both patients and caregivers, predict poor prognosis, rapid cognitive decline and disease progression, poor quality of life and increased cost. When facing BPSD, the first step is to exclude any physical or medical factors that can contribute to these symptoms, and then assess the nature and relevant factors involved in the process of BPSD. Start non-pharmacological treatment first, if without success, consider pharmacological treatment. The basic principles are: use antidepressants for mood symptoms, antipsychotics for psychotic symptoms and anticonvulsants for non-psychotic agitation. Periodic evaluation is mandatory for the necessity of continuous prescription. Owing to many potential adverse drug reactions (e.g. antipsychotics related stroke and death in dementia), physicians should take into account not only efficacy, but also safety concern and effectiveness.