Microbubbles have unique properties, existing stably for a long time, shrinking and disappearance (shrinking collapse) in a liquid to produce a gaseous supersaturated solution, and generation of hydroxyl free radicals. On the other hand, in the medical field, respiration and circulation management is given top priority, and oxygen administration and venous infusion routes are routinely carried out. Therefore, focusing on the property of the microbubble shrinking collapse phenomenon, if we can create an oxygen supersaturated infusion solution which directly oxygenate the blood, we can easily manage respiratory and circulatory conditions at the same time, which can be widely used for general treatment in various situations. Normally, when air bubbles are infused the blood, a thrombus is formed, which is dangerous and causes thromboembolism (infarction of the heart, lungs, brain, etc.). However, fine oxygen microbubbles that can easily pass through the thrombus removal filter (20-40㎛) of the CPB(cardio-pulmonary bypass) will naturally shrink and disappear (shrinking collapse) due to the nature of the microbubbles, so theoretically, thrombus can be eliminated. Therefore, the risk of embolism is small and considered safe. In the past, we have demonstrated that oxygen microbubble solutions with a diameter of 10 µm or less can be produced and the blood can be directly oxygenated. Furthermore, by combining a pressurized nozzle and ultrasonic waves, fine oxygen microbubbles with a diameter of 1.5 µm or less were produced in physiological saline, demonstrating the possibility and usefulness as an infusion solution. As for the application of the oxygen supersaturated infusion solution, it is expected to be used for emergency situations such as cardiopulmonary arrest, hypoxemia (pneumonia, respiratory failure, heart disease etc.), and ischemic diseases (myocardial/cerebral infarction, etc.). In general, chemotherapy and radiation therapy are known to induce cancer cell apoptosis and enhance their antitumor effects when they are placed in a hyper-oxygen state. If the oxygen supersaturated infusion solution are used in combination with anticancer drugs, the dose of anticancer drugs with strong side effects can be expected to be reduced, and the dose of antibiotics for infections (sepsis) can also be expected to be reduced.