The effectiveness of deferiprone (L1) and the influence of other factors were determined in a clinical setting. Patients of Southern Italian origin, affected by beta-thalassaemia major (n = 13: 7 M, 6 F), aged 10-28 years (median 18 years), were treated with L1 within a 'Controlled Programme' of the Italian Ministry of Health. Desferrioxamine could not be administered in these patients because of anaphylactic reactions or other serious side effects. L1 was considered to be effective when the liver iron concentration was reduced or stable as measured by biomagnetic liver susceptometry. L1 proved to be effective in 3 out the 9 evaluable patients. A high pre-L1 iron overload was the main clinical factor influencing L1 effectiveness.