Number of surgeries for the elderly is increasing year by year. Postoperative cognitive dysfunction, POCD, and delirium are typical failure's of higher brain function after surgery. The mechanism of POCD and delirium has been suggested to be associated with inflammation, but its details are unknown. Alzheimer's disease leads to derangement in cognitive function. The number of patients with Alzheimer's disease is expected to increase rapidly. There is a possibility that inhalation anesthesia exacerbates the pathology of patients with impaired higher brain function such as Alzheimer's disease. On the other hand, the another suspect, that propofol is safe. However, it should be recognized that these results became clear by basic research. Further clinical study is required.