We are concerned about the inappropriate use of haemopoietic growth factors in patients with severe aplastic anaemia (SAA). The treatment of choice for this disorder is bone-marrow transplantation from an HLA-identical sibling donor if the patient is younger than 45 years, but it must be done soon after onset before the patient becomes sensitised by multiple red-cell and platelet transfusions. Other patients should receive immunosuppressive therapy with antithymocyte globulin alone or with cyclosporin or oxymetholone. Haemopoietic growth factors may have a role in stimulation of granulopoiesis after immunosuppressive therapy, but there is no evidence that they can correct the underlying stem-cell defect in SAA, and therefore no justification for their use alone in newly diagnosed SAA. Such treatment is harmful because it delays bone-marrow transplantation, or immunosuppressive therapy in older patients and those without suitable donors, thus reducing the chances of a successful outcome.