Erythropoietin acts on the bone marrow so that it makes more red blood cells. It is used to treat some kinds of anemia. Anemia can happen in kidney failure, or from chemotherapy to treat cancer. The man-made hormone is made with cell cultures. The hormone can be used for blood doping in endurance sports although this is illegal in all athletic competitions.
It is also responsible for inhibiting the body process "Gluconeogenesis" (a process in your body which makes glucose from products other than carbohydrates), thus contributing to cure of type2 diabetes, glucose intolerance.