Supplemental oxygen, or oxygen therapy, is the use of oxygen as a detoxifier. This can treatment is beneficial for low blood oxygen, carbon monoxide toxicity, and even cluster headaches. Oxygen is required for normal cell metabolism, cellular respiration, detoxification, and much more. The use of oxygen therapy became common around 1917. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Oxygen is believed to be the most common treatment given in hospitals in the developed world. In order to receive the most benefit from this therapy you are given a mixture of nutrients that are vassal dilators. This means the nutrients help open the blood vessels, allowing the oxygen to reach, clean, boost, and detox more tissues in the body.