Abstract
Stress has long been suspected to play a role in the etiology of many diseases, and numerous studies have shown that stress can be immunosuppressive and hence may be detrimental to health. However, there are reasons to believe that under certain conditions stress may enhance, rather than suppress, immune function. This article discusses those reasons and reviews evidence that suggests that stress can, under certain conditions, enhance immune function. It then goes on to explore the functional consequences of a stress-induced enhancement of immunity and proposes a model for examining the relationships among stress, immune function, and health.