In 2012, according to the WHO (World Health Organization) and the International Alzheimer’s Association projections, there is a new dementia patient every 4 seconds worldwide, and there are currently about 8 million dementia patients in China, accounting for about 1/4 of the global dementia patients. many patients’ families believe that dementia is an untreatable disease and are therefore reluctant to send them to the doctor, but in fact a significant proportion of dementia patients are “reversible”. The causes of dementia can be broadly classified as degenerative, cerebrovascular, metabolic, malnutrition, hydrocephalus, and depression. Among the degenerative diseases, Alzheimer’s disease is the most dominant type of dementia, accounting for about 60%, and is indeed poorly treated at present because its pathogenesis is not fully understood. However, other causes of dementia are mostly partially correctable, and some can even be effectively reversed. For example, about 70% of patients with cerebrovascular disease have different degrees of cognitive decline one year after the onset of the disease. If early effective improvement of blood supply, hyperbaric oxygen therapy, etc., together with later cognitive rehabilitation exercises, most patients with cognitive impairment in the acute stage can return to normal; clinical dementia caused by hypothyroidism, estrogen deficiency, vitamin B12 deficiency, geriatric depression, etc., can be cured after early detection and symptomatic treatment. They can also be cured after early detection and symptomatic treatment. Therefore, family members should not delay the best time for treatment because of misconceptions.