Haematopoiesis (from Greek αἷμα, “blood” and ποιεῖν “to make”; also hematopoiesis in American English; sometimes also haemopoiesis or hemopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells.
In a healthy adult person, approximately 1011–1012 new blood cells are produced daily in order to maintain steady state levels in the peripheral circulation.