Haematopoietic growth factors are a family of genetically determined low molecular weight glycoproteins which regulate the proliferation and differentiation of haemopoietic cells through specific membrane receptors. GCSF and GMCSF reduce the morbidity from infections associated with the neutropenia induced by chemotherapy of onco-haematological neoplasia; EPQ totally corrects not only the anaemia of patients with chronic renal failure, but also 50 percent of anaemias related to chemotherapy; finally, the activity of IL 3 on platelet production seems to control the thrombocytopenia which restricts the use of therapeutics.