Confusion still exists in the diagnosis of drug-induced immune haemolysis (DIH). The aim of this study was to demonstrate antibodies specific to 5-fluorouracil (5-FU) in a patient with fatal immune haemolysis (IH). The case of a patient who died due to protracted IH is described. A 57-year-old female underwent treatment with oxaliplatin, 5-FU and folinic acid due to cholangiocarcinoma. Following drug administration, she was transfused because of a mild non-haemolytic anaemia and died following haemolysis. Serological testing including antibody screening, direct antiglobulin test and detection of drug-dependent antibodies was performed using standard techniques. The patient's serum was observed to be red in colour due to the presence of free haemoglobin prior to and following blood transfusion, and contained antibodies reactive with RBCs only in the presence of urine from several patients treated with 5-FU (ex vivo antigens). Drug-induced immune haemolysis (DIH) and metabolite-dependent antibodies should always be taken into consideration when a patient being administered any type of drug develops haemolysis.