Fever represents a normal and adaptative response developed in case of host aggression, notably by infectious agents, and is part of a large defense system, the acute phase response. Fever mediators are mainly derived from the host cells and are pyrogenous cytokines such as interleukin-1, tumour necrosis factor alpha, interleukin-6 or interferons which act at the hypothalamus level via prostaglandin E2. Although fever has been conserved through evolution, its beneficial effects in humans are not well-established.