People are generally under the impression that any method that can cure all diseases results in the failure to treat any disease. When we talk about the fact that hyperbaric oxygen can treat many diseases, this impression is naturally associated with it. The point here is that although hyperbaric oxygen cannot cure all diseases, it does cure many diseases. Oxygen is one of the three substances on which living organisms depend for survival. Oxygen, water, and food (including sugar, lipids, proteins, vitamins, trace elements), the lack of one of them, life will stop, and of its three substances only oxygen organism can not reserve the most, people do not supplement water life can be maintained for 6 days, people do not enter the food, life can continue for 6 weeks, but human life if the oxygen supply stops, its life can only survive for 6 minutes. Therefore, for the continuation of life, oxygen is the most important of the three substances. In terms of life support, oxygen is one of the three major support materials, and in reverse thinking, it can be said that at least one third of the diseases can be treated with hyperbaric oxygen, and as the replenishment of essential substances, the replenishment of oxygen is the most urgent. Once deficient, it must be replenished in a hurry. Water and food can be delayed for a while. The human life goes through many pathological changes from life to death. From the beginning of hypoxia to death, or death due to lack of nutrition, or death due to lack of water, the organism will go through many pathological changes. The many pathological changes that occur in this process due to three different causes are the same from a certain point of view, only the length of time is different. Water deprivation or lack of nutrition causes death by a long time to complete a series of pathological processes, while oxygen deprivation is a very short time to complete a series of pathological changes. In other words, hypoxia (one change) can cause many changes (many pathological changes) in a very short time. In other words, hypoxia (one change) can cause many changes (many pathological changes), and hyperbaric oxygen therapy during hypoxia can respond to many changes with one change. There are many other direct and indirect effects of hyperbaric oxygen, such as antibacterial effects (treatment of anaerobic infections), antiviral effects (treatment of viral encephalitis, treatment of AIDS, etc.), and the effect of compressing the gas confined in the body (treatment of gas embolism and decompression sickness, etc.). Hyperbaric oxygen has indirect therapeutic effects by regulating many physiological functions, such as regulating endocrine function, which is equivalent to glucocorticoid and insulin; for example, it has double regulating effects on cardiovascular system, on the one hand, it can constrict blood vessels to raise blood pressure and prevent tissue edema, and on the other hand, it is equivalent to beta blocker on heart. The effect of hyperbaric oxygen on the cardiovascular system has a dual regulatory effect, on the one hand, it can constrict blood vessels to raise blood pressure and prevent tissue edema, and on the other hand, it acts on the heart as a beta blocker. Hyperbaric oxygen has a certain regulatory effect on almost all systems of the body. After extensive practice and research, more than 100 indications for hyperbaric oxygen therapy have been published in China (see table). The number of indications for hyperbaric oxygen therapy will continue to increase as research progresses and practice becomes more widespread. Hyperbaric oxygen can treat many kinds of diseases, and it is not a general lie that can cure all diseases.