A 54 year-old female patient with polycuthemia vera developed subdural and intracerebral haemorrhages after a minor head trauma caused by fall. At the time of hospitalisation the patient was conscious, had no paresis, but presented with severe sensorimotor aphasia. Blood analysis displayed thrombocytopenia, thrombocyte function disorder and coagulopathy. As emergency surgery was required because of the intracranial hematomas, the patient received freshly frozen plasma, desmopressin and tranexamic acid to improve coagulation. During surgery and in the immediate postoperative period no complications developed. Aphasia improved gradually. The consulting haematologist described this case as a polycythaemia that developed into myelofibrosis. Hydroxycarbamide was prescribed for treatment.