Erythropoietin

Erythropoietin or EPO is a naturally occurring hormone that regulates the production of red blood cells in the bone marrow, as well as performing other functions. In its pharmaceutical preparation, it is used in treating many types of anemia, some types of cancer and some neurological diseases.
However, it is also abused by athletes who participate in endurance sports such as cycling. 
Erythropoietin at Wikipedia
Category:Pharmaceuticals