Prolonged oxygen intake is not necessarily good for the body, and even oxygen poisoning may occur. Normal people suffer from many diseases with abnormal cardiorespiratory function due to the fast pace of life, high brain and physical exertion and increased pressure. Oxygen intake within a short period of time on a daily basis can have the effect of reducing cerebral overdraft, relieving work pressure, helping to relax and reducing cardiovascular diseases. And COPD patients can be treated with oxygen inhalation, which can significantly relieve patients’ dyspnea and improve the quality of life and patients’ survival rate. However, if a large amount of inhalation of high concentration of oxygen for a long time, for example, continuous inhalation of 100% oxygen for 24 hours, it may cause oxygen toxicity, divided into pulmonary oxygen toxicity, cerebral oxygen toxicity and ocular oxygen toxicity. Oxygen toxicity can occur easily in the following situations: prolonged use of ventilator to supply high concentration of oxygen, high air pressure in hyperbaric chamber and too long oxygen intake time, too high oxygen concentration in infant feeding tank, etc.