SummaryThe author reviews a case of myeloma in which the diagnosis was confirmed by a biopsy of the pelvis. He relates the results obtained by giving pentamidine as indicated by Snapper.The patient received this drug twice : at the first time 1,19 gr, later on 1,12 gr.From aclinicalpoint of view the pain was reduced and the patient improved. No significantblood changes,were observed : globulinemia was not reduced. Bence Jone’s albuminuria persisted, but the treatment was followed by an increase of theabsolute number of polynuclearcells associated with a decrease of the lymphocytes.X rays studiesdid not show important changes although recalcification was observed in several points.It must be pointed out that hyperleucocytosis with polynucleosis has not been described until now and it is a fair possibility that pentamidine awakes an adreno-cortical response.Such a mechanism is to be considered when the general mode of action of anti-cancerous drugs is discussed.