A reduction in lung capacity to oxygenize blood as well as in cardiovascular capacity to distribute blood may cause hypoxemia, which could then lead to tissue hypoxia and cellular death. The aim of oxygen treatment is to supply the minimum oxygen concentration needed to achieve adequate tissue oxygenation. There are various methods that can be used to supply oxygen, and the amount of oxygen requirement could also be calculated. Treatment methods are classified into STOT and LTOT. The benefit of oxygen treatment is increased survival, influence on the blood vessels, improved exercise capacity, and positive influence on the respiratory and neuropsychological systems. As with the case with pharmacological treatment, oxygen should be administered at certain doses to achieve greatest efficacy with the least toxicity.