Oxygen is essential for human survival, and lack of oxygen can have a significant impact on people. Oxygen inhalation is to inhale oxygen through natural breathing for oxygen therapy, which is a common method of oxygen therapy. The indications for oxygen inhalation are wide, mainly the following: 1, hypoxemia caused by respiratory system diseases, common are bronchial asthma, chronic obstructive pulmonary disease and other lung infectious diseases caused by inadequate pulmonary ventilation. 2, atmospheric hypoxia, common for people in a plateau environment, through the inhalation of outside oxygen to supplement sufficient oxygen. 3, increased oxygen consumption, common are pregnant women, patients with high fever, chills and stroke patients.4. Hypoxia caused by circulatory dysfunction, such as patients with cardiac insufficiency, shock, etc., and the symptoms are relieved to some extent by oxygen inhalation.5. Tissue utilization of oxygen impairment, such as cyanide poisoning patients by inhaling high concentrations of oxygen to increase the partial pressure of oxygen and improve the oxygen uptake capacity of tissue cells, thus improving the symptoms of hypoxia. Except for a very small number of patients who develop oxygen toxicity, oxygen inhalation is generally not contraindicated, and normal people can also inhale oxygen.