Because of recent changes in Federal Food and Drug Administration (FDA) regulations, new medications may now be marketed before completion of rigorous controlled testing. In order to understand the ramifications of this development, it is instructive to recall the introduction of the sulfonamides in the 1930s. The sulfonamides, the first effective antibacterial agents, were marketed in an era of relatively few regulations. Although investigators at times designed controlled trials to evaluate use of the drugs, both researchers and practitioners generally prescribed them for severe infections, despite a lack of conclusive data as to their efficacy. The clinical usefulness of sulfonamides for a given condition often became known through uncontrolled case studies and comparisons with historical control groups. Given the relaxation of FDA regulations, this method of drug evaluation may again become more commonplace.