**1. Introduction**

The role of histamine signaling in the brain in thermoregulation has been unraveled in various organisms. The preoptic area/ anterior hypothalamus (PO/AH), region which contains thermoeregulatory neurons, is the main locus in which histamine affects body temperature. Histamine has a complex influence on thermoregulation and its circadian cycle and appears to be involved also in numerous pathological responses that involve changes in core body temperature. The neurotransmitter activates several signaling pathways involving H1, H2 and H3 subtype receptors and recruits distinct neuronal networks to modulate body temperature. In this review we describe the mechanism involved in the hypothalamic control of thermoregulation, the signaling mechanisms activated by histamine in the brain, the evidence for its role in thermoregulation as well as recent advances in the understanding of the cellular and neural network mechanisms involved.
