Oxygen is one of the most widely available and used therapeutic agents in the world. However, it is all too
easy forget that oxygen is a prescribable drug with specific biochemical and physiologic actions, a distinct
range of effective doses and well-defined adverse effects at high doses. The human body is affected in
different ways depending on the type of exposure. Short exposures to high partial pressures at greater
than atmospheric pressure lead to central nervous system toxicity, most commonly seen in divers or in
hyperbaric oxygen therapy. Pulmonary and ocular toxicity results from longer exposure to elevated
oxygen levels at normal atmospheric pressure.