Indications for hyperbaric oxygen, mainly the following: I. Various causes of cerebral ischemia and hypoxic diseases, such as carbon monoxide, carbon dioxide poisoning, because of drowning, laryngeal edema, anesthesia accident, resulting in hypoxic-ischemic manifestations. Second, anaerobic bacterial infections, including gas gangrene, tetanus, etc. Hyperbaric oxygen can provide a high concentration oxygen environment to promote bacterial death and organism recovery. Third, it is a treatment tool for recovery from traumatic brain injury and cerebral hemorrhage, which can significantly improve the prognosis of brain diseases. IV. Diseases that require high concentration to help recovery. For example, vasculitis, intractable ulcers, osteofascial compartment syndrome, arterial thrombosis, poor bone healing, crush injuries, etc. V. Unusual acne, rosacea, erythema nodosum, neurological and diabetic dermatitis can also be treated with hyperbaric oxygen. Contraindications to hyperbaric oxygen are as follows: i. Patients with open pneumothorax or hemothorax, combined with active bleeding, should not be treated with hyperbaric oxygen. Second, patients whose blood pressure is too high or too low and unstable should not use hyperbaric oxygen therapy. Too high or too low blood pressure can lead to the risk of cerebral hemorrhage and coma in patients. Third, patients with pulmonary herpes are prone to rupture of pulmonary herpes, resulting in serious complications. IV. Patients with severe infections, especially respiratory infections, should not be treated with hyperbaric oxygen, which will further aggravate the infection. V. Patients who are pregnant, have poor cardiopulmonary function, or have severe bleeding tendency should also not use hyperbaric oxygen therapy.