The relation between antibiotic control and resistance was assessed by review of selected journal articles from 1988 through 1994. Most studies of control or monitoring do not report susceptibility pattern as an outcome measure. Several aspects of bias and confounding prevent more than analysis of temporal association between antibiotic use restriction and resistance pattern. However, in a few institutions there has been an increase in susceptibility to antimicrobials following intensive control or monitoring. Moreover, in a few hospitals, intensive antibiotic control for selected drug-organism pairs was associated with a high prevalence of susceptibility, and the proportion susceptible fell abruptly when control or monitoring was relaxed or removed. These examples, coupled with the recent emergence of new resistant organisms, justify attempts to determine the value of intensive antibiotic control as a preventive practice. Because these studies were performed in single institutions, their power to distinguish associations was poor. Cooperative multicenter studies are needed in which selection and classification biases are addressed prospectively, and in which confounding factors are controlled.