Delayed encephalopathy dementia is usually difficult to recover from. Delayed encephalopathy dementia is a condition in which a patient with carbon monoxide poisoning develops dementia. Some patients go home with dementia manifesting itself with mental abnormalities in the form of decreased activity, unresponsiveness, inarticulateness, disorientation, and decreased numeracy. Once found to have delayed encephalopathic dementia, it means that the brain has substantial changes, the central nervous system of the brain can not be regenerated, and it is generally more difficult to fully recover from the lesions that lead to necrosis. Therefore, when carbon monoxide poisoning occurs, during the acute stage should be treated in a timely manner, in accordance with the doctor’s instructions, to reduce the probability of late-onset encephalopathic dementia.