Oxygenation, also known as oxygen therapy or supplemental oxygen, is a method of using oxygen as a medical treatment. It can be used to treat conditions including low blood pressure, low blood oxygen, carbon monoxide poisoning, cluster headaches, and to maintain adequate oxygen inhalation when giving inhalation anesthetics. Oxygen is given by oxygenation and can be given by a variety of methods, including nasal cannula, face mask, or in a hyperbaric chamber. Oxygen is required for normal cellular metabolism, but it is also important to note that too high a concentration can lead to oxygen toxicity when using oxygenation. This can cause lung damage, for example, or lead to respiratory failure in the patient. Excessive concentrations of oxygen without humidification can also dry out the nasal passages and damage the respiratory tract and nasal mucosa. Additionally, in acutely ill patients, overuse of oxygen increases the risk of death. Oxygen therapy for home use can be provided through oxygen tanks or oxygen concentrators. Oxygenation is considered contraindicated in some cases of strong oxidant poisoning, such as paraquat poisoning, and attention should be drawn to this.