Haloperidol is the most commonly used medication for the treatment of delirium and psychosis in the critically ill patient. Whilst generally considered to be safe, haloperidol has been associated with a number of important cardiovascular side effects. The major toxicities include hypotension, cardiac arrhythmias and prolongation of the corrected QT (QTc) interval. In particular, torsade de pointes, a polymorphic ventricular tachyarrhythmia, has been associated with both intravenous and oral haloperidol administration. The management of torsade de pointes consists of discontinuation of the possible offending agent(s), correction of electrolyte abnormalities, administration of magnesium sulfate and, if necessary, overdrive pacing. Although clinicians should be aware of this potentially lethal complication of intravenous haloperidol therapy, it should not deter clinicians from using intravenous haloperidol to treat acute agitation in the critically ill patient with a normal QTc.