OBJECTIVE Rapid and safe tranquillisation is sometimes unavoidable. We conducted this systematic review to determine the value of the combination haloperidol plus promethazine, frequently used in Brazil. METHODS We searched the Cochrane Schizophrenia Group's Register and included all randomised clinical trials involving aggressive people with psychosis for which haloperidol plus promethazine was being used. We reliably selected, quality assessed and extracted data from all relevant studies. RESULTS We identified four relevant high quality studies. The combination haloperidol plus promethazine mix was compared with midazolam, lorazepam, haloperidol alone and olanzapine Intramuscular. In Brazil, haloperidol plus promethazine was effective with over 2/3 of people being tranquil by 30 minutes, but midazolam was more swift and in India, compared with lorazepam, the combination was more effective. Over the next few hours reported differences are negligible. Haloperidol given without promethazine in this situation causes frequent serious adverse effects. Olanzapine is as rapidly tranquillising as haloperidol plus promethazine, but did not have an enduring effect and more people needed additional drugs within 4 hours. CONCLUSIONS All treatments evaluated are effective, but this review provides compelling evidence as to clear advantages of the haloperidol plus promethazine combination.