A person in a coma is not conscious. Coma is a type of complete loss of consciousness and is a clinically critical condition. The occurrence of coma suggests that the patient’s cerebral cortical function has been seriously impaired. The main manifestations are complete loss of consciousness, loss of random movements, and delayed or loss of response to external stimuli, but the patient still has breathing and heartbeat. Coma can be caused by a variety of circumstances, most of the causes of coma are related to brain injury, clinically it is mainly divided into two categories of intracranial and extracranial lesions, usually increased intracranial pressure, intracranial hemorrhage, cerebral hypoxia and so on can cause brain damage leading to coma. After coma, emergency treatment should be carried out immediately: send the patient to the hospital as soon as possible; at the same time, keep the patient’s respiratory tract open, clean up the airway in time, use the oropharyngeal tube for those who have greater respiratory resistance, and the patient should adopt a stable lateral position to prevent the pharyngeal tissues from falling down and blocking the respiratory tract, and also to facilitate the drainage of secretions, and to prevent the gastrointestinal tract from the contents of the reflux leading to the misaspiration. If there is a coma condition must go to the hospital as soon as possible to timely treatment, so as not to delay the condition.