Shortly after the use of thiouracil as an antithyroid drug became common its potentialities as a depressant of polymorphonuclear cell formation became apparent. A number of cases were reported in which this complication resulted in death. The profession was cautioned that great care be exercised in its use and that frequent blood cell counts be done during the course of therapy. The development of propylthiouracil resulted from the search for a more potent and less toxic drug. Propylthiouracil is the only antithyroid drug listed in the 1948 edition of "New and Nonofficial Remedies." It is cautioned that this drug is capable of producing toxic reactions the severity of which is unpredictable—the most severe and serious one being agranulocytosis. That leukopenia can occur with the use of propylthiouracil has been mentioned in a number of articles. McCullogh, Hibbs and Schneider1reported 1 case of granulocytopenia in 218 cases studied. Eisenmenger