BACKGROUND: Makeup greatly impacts normal social lives but can also be a non-pharmacological form of therapy for dementia. OBJECTIVE: To evaluate the therapeutic effect of makeup therapy. METHODS: We carried out a prospective interventional study on female nursing home residents with dementia, focusing on the chronic therapeutic effect of makeup therapy. Thirty-four patients who received either only skin care (control group, n = 16) or skin care plus makeup therapy (makeup therapy group, n = 18) once every 2 weeks for 3 months were assessed. RESULTS: Three months of makeup therapy significantly improved the Mini-Mental State Examination (MMSE) score compared with control patients ( *p <  0.05). Artificial intelligence (AI) software revealed that the appearance of age decreased significantly in the makeup group compared with the control, especially among patients without depression ( *p <  0.05). Furthermore, a larger AI happiness score was significantly correlated with a greater improvement of ADL in the makeup therapy group (r = 0.43,  *p <  0.05). CONCLUSION: Makeup therapy had a chronic beneficial effect on the cognitive function of female dementia patients, while the chronic effect of makeup therapy on facial appearance was successfully detected by the present AI software.