The causes of vegetative person include cerebrovascular disease, trauma, poisoning, central nervous system infection and so on. 1. Cerebrovascular disease: if there is a large infarction in the brain stem or a large cerebral infarction in the cerebral hemisphere, there may be a disturbance of consciousness, and in severe cases, the person may become a vegetable. 2. Trauma: if experiencing severe craniocerebral trauma, it may also lead to vegetative state of existence. 3. Poisoning: If there is carbon monoxide or drug poisoning, it will destroy the structure of the central nervous system, and in severe cases, a vegetative state may occur. 4. Infection of central nervous system: especially when suffering from severe encephalitis, it may also lead to the emergence of vegetative state. Therefore, in normal life, we should pay attention to avoid cerebrovascular disease, trauma, poisoning and central nervous system infection, etc. Once this state develops, the prognosis is often unsatisfactory.