SummaryOxymetholone, a non-virilising androgen, active orally and known to have an active stimulant effect on the bone marrow, was given to an unselected group of 23 patients with various forms of malignant disease not suitable for surgery; in all but one it was given in conjunction with cytotoxic drugs. Although many of the patients were also receiving prednisolone the beneficial effect on the haemoglobin levels was striking and statistically significant. Twelve out of 23 patients (52%) showed a significant rise in haemoglobin level and when 3 patients are excluded, in whom no adequate assessment could be made, this proportion rises to 60%.It appears that oxymetholone is a useful drug for stimulation and protection of the bone marrow inpatients receiving cytotoxic therapy and is, therefore, a useful addition to the chemotherapy of malignant disease.