Angioedema is a serious adverse drug reaction that can rarely be associated with trifluoperazine treatment. We present the case of a 44-year-old male with an established diagnosis of schizoaffective disorder, for which trifluoperazine therapy was considered. He presented to the emergency department with bilateral lower limb oedematous painful erythematous swelling that eased off completely when trifluoperazine was stopped. The possibility of allergic reaction, such as angioedema, should always be kept in mind by psychiatrists and mental health professionals when prescribing trifluoperazine antipsychotic.