Previous clinical trials have demonstrated the efficacy of yokukansan, a traditional Japanese medicine, for the treatment of behavioral and psychological symptoms of dementia (BPSD). However, less evidence is available for the treatment of BPSD with yokukansankachimpihange (YKSCH), which consists of yokukansan and two additional herbal ingredients. The present study was conducted to investigate the efficacy and safety of YKSCH for treating BPSD in patients with Alzheimer's disease (AD). We enrolled outpatients with mild-to-moderate AD who exhibited BPSD and obtained a Neuropsychiatric Inventory (NPI) score of >3 including subscale scores for "agitation", "anxiety", "irritability", and "sleep and night-time behavior change". A daily YKSCH dose of 7.5 g was administered for 12 weeks with concomitant administration of anti-dementia medication. BPSD was evaluated using the NPI at baseline and every 4 weeks during the intervention. We also examined apathy using the Japanese translation of the Apathy Scale, the short version of the Japanese version of the Zarit Caregiver Burden Interview, and the Modified Crichton Rating Scale for Predicting Activities of Daily Living. Cognitive dysfunction was evaluated using the Mini Mental State Examination and the AD Assessment Scale-Cognitive (Japanese version). Five participants were enrolled. The NPI total score tended to decrease between the baseline