Abstract
A pregnant anti-Rh sensitized woman was treated with massive doses of gamma-globulin. Subsequently there was no increase of the antibody-titer until 1 month after delivery of a Rh-positive healthy boy. These results are parallel to the diminution of anti-sheep red cell agglutinin production in rats (and mice) injected regularly with high quantities of homologous serum. Substitutive-inhibitory gamma-globulin treatment seems to be useful in preventing stillbirth due to mater no-fetal blood incompatibility.