The clinical manifestations of oxygen toxicity are as follows: 1. Pulmonary oxygen toxicity, the patient’s symptoms are similar to acute bronchitis, initially the symptoms of bronchial irritation caused by upper respiratory tract infection are dominant, there is discomfort, irritation, burning pain behind the sternum, accompanied by dry cough. Subsequently there will be pain behind the sternum, and the pain will spread along the bronchial bundle to the whole chest, and the pain will gradually increase during inspiration, as uncontrollable cough. 2. Convulsive oxygen toxicity, the patient will have facial and muscle twitching, lip tremor, symptoms of autonomic nerves, accompanied by dizziness, palpitations, pallor, abnormal sensation, emotional irritability, anxiety, euphoria, etc. 3. Convulsive oxygen toxicity and cerebral oxygen toxicity , patients with this condition will have grand mal seizures or peripheral tonic spasmodic seizures.