The vegetative state is a clinical state with a sleep-wake cycle but with loss of self and environmental awareness and retention of some or all hypothalamic-brainstem autonomic functions. The state can be a temporary manifestation of the recovery process from acute (slow) brain damage, or it can be the permanent end of the above damage that cannot be recovered. A vegetative state lasting for more than 1 month is called a persistent vegetative state. The diagnostic criteria for the vegetative state are as follows: (1) Absence of any manifestation of self and environmental awareness and inability to communicate with others. (2) Inability to respond to visual, auditory, tactile, or injurious stimuli with sustained, repeatable, purposeful, or spontaneous behavior. (3) There is no evidence of verbal comprehension or expression. (4) Presence of an intermittent arousal state with a sleep-wake cycle. (5) Hypothalamic-brainstem autonomic function is sufficiently preserved to ensure survival under medical and nursing conditions. (6) Urinary and fecal incontinence. (7) Preservation of cerebral neural reflexes (pupillary-to-light reflex, cephalic reflex, corneal reflex, vestibulo-ocular reflex, and vomiting reflex) and cremaster reflex to varying degrees.