The hidden period of delayed encephalopathy refers to the “false recovery period” of 2-60 days after carbon monoxide poisoning. Some patients may spontaneously show improvement after acute carbon monoxide poisoning, and their condition suddenly worsens after the “false healing period” of 2-60 days. Patients may show slow reaction, decreased calculation power, memory loss, hemiplegia, convulsions, etc., and may be accompanied by anxiety, depression and other mental symptoms, incontinence, and even sleep, coma, etc. When carbon monoxide poisoning occurs, timely medical treatment, such as hyperbaric oxygen therapy, brain protection therapy, etc., and in daily life should be strengthened to prevent carbon monoxide poisoning risk awareness.