Oxygen saves lives—but too much can quietly harm them. This course unpacks the pharmacology of oxygen as a true “drug,” exploring its dose–response curve, organ-specific toxicity, and the evidence behind conservative versus liberal oxygen strategies. You’ll learn how hyperoxia impacts the lungs, heart, brain, neonates, post-arrest and post-MI patients, and those on long-term oxygen therapy—then translate that knowledge into practical FiO₂ targets and bedside decisions that protect your patients from both hypoxia and oxygen-induced injury.