We all know that when we suffer from fever we feel sleepy and do not feel like eating. Our mothers and grandmothers provided sound wisdom during our bouts of illness with fever. They recommended rest and tried to make us eat, advocating folk remedies like chicken soup or various teas. The physiologic roles of mediators of fever such as IL-1, TNF-α, IL-6, and prostaglandins account for some of the physiological changes in the sleep/wake cycle and in appetite (1, 2). Prostaglandins are involved in the induction of sleep, while TNF-α triggers loss of appetite and pyrexia. However, we are now learning that the interconnections between molecules that modulate brain function and those that mediate the immune response are more intertwined than we had previously imagined.