The present paper discusses appearance and course of neuroleptic induced hypothermia of a 36 years old woman suffering from periodic catatonia and a 38 years old seriously mentally handicapped man. Analysis of clinical studies and pharmacological tests with animals about body temperature changes caused by neuroleptics yields that these may lead to hypothermia as well as hyperthermia, depending on individual disposition and dose, which is mainly a result of their effect through dopaminergic neurons of the hypothalamus, which controls thermoregulation, and of their influence on vasomotoric mechanisms of vessels of the skin. Though hyperthermic changes are more hazardous and occur more frequently hypothermia by neuroleptic agents is clinically relevant as shown by the summarizing presentation of previously released case reports: hypothermia is found at neuroleptic medicated healthy volunteers and at psychiatric patients with or without physical illness, at which hypothyreosis and impair of the brain seem to represent special risks.