This article reviews published research on the physiology of histamine H3-receptors. The function of this inhibitory autoreceptor, its localisation and influence on histaminergic neurones as well as histamine-controlled processes are presented together with the role of H3-receptors in the vestibular system. In addition to a summary of the properties of the main H3-agonists and -antagonists, the pharmacology of betahistine and its place in the treatment of vertigo are discussed.