To prevent nosocomial infections, hospitals use two types of procedures: routine patient care practices (handwashing, for example), which are used in appropriate circumstances on all patients, and more intensive isolation precautions, which are implemented only when patients are suspected of having particular infections. Aspects of these current practices, however, may limit their effectiveness. We propose the use of body substance isolation, a simpler alternative system that is used for all patients, not just in response to a specific diagnosis, and that emphasizes the increased use of barrier precautions, especially gloving, when contact with potentially infectious bodily secretions is anticipated. Because of its rationale and simplicity, body substance isolation has been enthusiastically accepted at our hospitals, and we encourage others to consider and evaluate this approach.