Sir,Neuroleptic malignant syndrome, malignant hyperthermia and hypothermia are all problems of thermoregulation, which are rare, but still contemplated as life threatening situations.[1] They are generally precipitated by neuroleptics and psychotropic medications that cause alterations in neurotransmitter levels. Hypothermia or low body temperature can be caused by the shifting of the thermoregulatory balance caused by inactivation of the 5HT2 receptors and activation of the D2 receptors.[2] This has been seen with the second-generation antipsychotic, risperidone.[3] Conversely, an older antipsychotic “Haloperidol” is known to turn the thermoregulatory balance toward hyperthermia.[4] This is perhaps due to dopamine inactivation and serotonin overactivation.[4] An intact blood brain barrier is also thought to be essential in the normal thermoregulatory function. Altered calcium signaling in the mitochondria of hypothalamic cells, potentially as a result of administration of antipsychotic drugs, may result in cell death, compromising the integrity of the blood brain barrier.As human beings are homeotherms they require a constant core body temperature to survive. This is achieved by neuronal structures with thermoregulatory response centers located in the brainstem and spinal cord.[5] The preoptic region in the hypothalamus acts as a coordinating center and contains neurons sensitive to minute changes in both hypothalamic and core temperature and from here it sends signals to lower effector neurons to maintain temperature.[5] Many studies have implicated calcium signaling as the basis for thermoregulation. If the body experiences extreme variations in temperature, either due to some genetic factors or changes in the internal or external factors, they seem to be caused by altered calcium signaling working at the neurotransmitter level markedly in the region of the anterior hypothalamus.[14]As there is a great risk of variations in temperature in people, who are put on antipsychotic medications a close monitoring of patients and follow-up of such people is necessary. In cases of hypothermia, patient's temperature should be monitored and slight changes in behavior or new infections should be taken as a warning sign.[2] Moreover, administration of a centrally acting calcium channel blocker must be considered a safe adjunct to neuroleptic therapy reducing the deleterious side-effects of the treatment.[1]