EPO stands for erythropoietin, which is a hormone that is produced naturally in the human body by the kidneys. EPO stimulates the production of red blood cells, which carry oxygen from the lungs to the body’s tissues.

EPO can also be produced synthetically and used as a medication to treat anemia in patients with chronic kidney disease, cancer, or HIV infection. It can also be abused by athletes as a performance-enhancing drug because it increases the oxygen-carrying capacity of the blood, allowing athletes to perform better in endurance sports. However, the use of synthetic EPO in sports is illegal and can have serious health consequences.