To the Editor:— The case of the recently publicized "Rh baby" suggests need for an evaluation of the current method of treatment in erythroblastosis fetalis and of its effectiveness. The procedure usually undertaken is the administration of relatively small amounts, 50 to 60 cc. once daily, of compatible blood from an Rh negative donor. The object is the replacement of the "hemolyzed" Rh positive erythrocytes of the infant with cells which will not be "hemolyzed" in order to preserve an adequate oxygen-carrying capacity of the blood. This replacement is usually the only therapeutic measure considered necessary, since "hemolysis" is conceived to be the cause of all the other abnormal symptoms and findings. The effectiveness of the current treatment can be judged by the unfavorable prognosis commonly held. Potter recently reported the production of an unaffected child by the artificial insemination of an Rh negative woman with semen from an Rh