Malignant syndrome is a rare and serious adverse reaction. Patients present with fluctuating consciousness, muscle tonicity, hyperthermia, and autonomic instability as the main clinical manifestations. It is prone to occur during treatment with drugs such as haloperidol, chlorpromazine, and fluphenazine, and may be associated with the development and progression of the malignant syndrome in the context of rapid drug dosing, excessive dosage, dehydration, nutritional deficiencies, comorbid somatic disorders, and factors of hot climate. An elevated concentration of creatine phosphokinase can be found, but is not an indicator of a confirmed diagnosis.