The behavioral and psychological symptoms of dementia (BPSD) are experienced by up to 90% of patients with dementia throughout dementia. This study aims to investigate the effect of aromatherapy on agitation in patients with dementia in the community. This prospective cohort study was conducted at a single day-care center for patients with dementia located in northern Taiwan with 2-week and 4-week follow-ups, com-paring the severity of agitation between 3 measure points as the primary outcome. The aromatherapy was performed over 5 consecutive days for 4 weeks. Throughout the four-week observation were analyzed by GEE. Significant differences were found in the Chinese version of Cohen-Mansfield Agitation Inventory (CCMAI) total agitation score (ss=-3.622, p=0.037) and physically non-aggressive behavior subscale (ss=-4.005, p=0.004) between aromatherapy group and control group. The severity of dementia-related agitation, espe-cially the severity of physically non-aggressive behavior in demented patients, could be significantly reduced by a four-week intervention of aromatherapy.(c) 2023 Elsevier Inc. All rights reserved.