The Commentary by Dr. Norman Kretchmer, appearing as the lead article in the October, 1962, issue of Pediatrics, eloquently expresses the concern that all thoughtful physicians have for the harm that attempts at progress in medical care may bring about. Although the total benefit that our drugs, hormones, and vaccines accomplish for our public far outweighs the harm, we look back with a shudder at some of the mistakes. To mention a few, the Lübeck disaster with BCG; several frightening experiences in the early attempts at poliomyelitis immunization; the early mistake in the manufacture of the Salk vaccine; the horrible disaster from retrolental fibroplasia about which I feel particularly guilty; the increase of brain damage from bilirubinemia resulting from a general prophylactic use of the sulfa drugs; and now this most horrible disaster from thalidomide; all should keep us in a healthy state of alert worry.