More than 70 years ago, a new age in endocrinology was just beginning with the first purification of a hormone, adrenaline. As early as 1930, almost immediately following its first use, cases of adrenaline-associated sepsis were reported. From this time, there have been reports associating the elaboration of neuroendocrine hormones, such as adrenaline, with infectious disease. The most widely accepted theory to explain the ability of hormones to influence the course of infection involves the suppression of the immune system. The theory that the infectious microorganism itself might be equally responsive to the host's neuroendocrine environment has not been considered. It is the intent of this article to introduce a new perspective to the current understanding of the factors that mediate the ability of bacteria to cause disease, and to demonstrate that neuroendocrinology and microbiology intersect to form the interdisciplinary field of microbial endocrinology.