How long it takes for a spontaneously breathing comatose patient to wake up is related to the cause of the illness and the condition; less severe cases may wake up within minutes or days, while more severe cases may not wake up at all. Common diseases leading to coma include traumatic brain injury, carbon monoxide poisoning, cerebrovascular disease, intracranial malignant tumors and so on. 1. Traumatic brain injury: mild traumatic brain injury with concussion may wake up within minutes; patients with cerebral contusion may wake up within minutes or hours through active treatment; severe brain injury may result in persistent coma. 2. Carbon monoxide poisoning: after mild carbon monoxide poisoning, patients may wake up in a short period of time after timely opening doors and windows and detaching themselves from the place of poisoning, while severe cases may be life-threatening and difficult to wake up. 3. Cerebrovascular disease: including cerebral hemorrhage and cerebral infarction, etc. If the area of hemorrhage or infarction is relatively small, the treatment can be recovered in time, and the patient can be awake within a few days. Large cerebral infarction or cerebral hemorrhage may cause brain hernia and death. 4. Intracranial malignant tumors: If the patients with malignant tumors in the middle or late stage have consciousness disorder, it is often difficult to recover, and the recovery time may take several years or even longer. How long will a comatose patient with spontaneous breathing wake up, it is recommended to consult a professional doctor in the hospital in time.