An 85 year-old man was admitted due to chronic diarrhea, malnutrition, weight loss, and delirium. The patient presented with different phenotypes (including hyperactive, hypoactive, and mixed type) of delirium during hospitalization. We had evaluated this patient by comprehensive geriatric assessment to recognize delirium, found the remediable factors of delirium, provide adequate supportive care and interdisciplinary care to prevent complications. After evaluation and treatment, the patient reported significant improvement and gradually restored to his baseline functional status after discharge.