Risperidone is an atypical antipsychotic drug, which is used in schizophrenia and also to treat excitation and aggression in patients with delirium. Risperidone has a low risk of haematotoxicity because of its different chemical and pharmacological profile compared to other drugs such as clozapine. Haematological abnormalities have life-threatening complications, especially neutropenia, leucopenia and agranulocytosis, but their effect on erythrocytes in adults is less well known. We highlight the effect of risperidone on erythrocytes and the mechanism that leads to anaemia. To the best of our knowledge, this is the only report of 2 patients showing combinations of mechanisms leading to risperidone-induced anaemia.