The appropriate use of antimicrobial agents must be reviewed at frequent intervals because new information becomes available about clinical pharmacology and alterations in the patterns of antimicrobial susceptibility. Each year there appear reports of major changes that require reconsideration of the choice and manner of application of some commonly used agents. Hexachlorophene had been used routinely for bathing newborn infants for more than 15 years before evidence that it may cause central nervous system poisoning prompted the Food and Drug Administration to recommend the abandonment of this routine practice.1More recently, strains ofHaemophilus influenzaetype B highly resistant in vitro to ampicillin have been reported from widely separated locations in the United States.1,2These strains were isolated from children with meningitis or sepsis, and bacteriological and clinical failures of therapy with ampicillin corroborated the results of these in vitro susceptibility tests. Physicians who had been using ampicillin