Carbimazole is an antithyroid drug of the thionamide class which is used in the treatment of hyperthyroidism. Rarely, use of this drug may be associated with the development of agranulocytosis and neutropenia with the consequent risk of sepsis. We present the case of a 50-year-old female who developed rapidly progressive Pseudomonas aeruginosa septicemia in the setting of panycytopenia approximately 4 weeks following the commencement of carbimazole therapy for Graves' disease. She died shortly after presentation to hospital and the case was referred to the coroner as the death was unexpected and the clinical course was considered unusual. Relatively sudden, unexpected deaths resulting from hematological/endocrine causes are uncommonly encountered by forensic pathologists and this case serves to illustrate the enduring value of the autopsy in providing important clinicopathological correlation to clinicians.