Thirty patients with cystic fibrosis, 24 of whom had longstanding low serum vitamin E, were treated with 50 mg alpha-tocopherol acetate per day for periods of 18-24 months. None of the patients received haematinics during the study period. Throughout the period of study the overall clinical state of the patients did not alter significantly. The serum vitamin E level increased in all patients, but to a variable degree which was not related to the severity of steatorrhoea. A range of nutritional parameters, including anthropometry, vitamin levels, essential elements, haemoglobin and albumin, as well as dietary intake and faecal fat excretion, were assessed at the beginning and end of the study. Haemoglobin was the only parameter to change significantly from 13.14 to 13.47 g/100 ml. Twenty one of the 30 patients showed some increase in haemoglobin values and this increase could not be related to clinical state, fat absorption or dietary intake but was related to the improved vitamin E status.