Acute methotrexate intoxication occurred in 4 patients despite adequate alkaline hyperhydration and classical folinic acid rescue. Three of these patients had no previous risk factor. Charcoal haemoperfusion with haemodialysis was promptly instituted and the methotrexate blood levels rapidly decreased, avoiding further renal damage and multisystemic involvement. Chemotherapy could subsequently be performed in 3 of the 4 patients without delay and toxicity. Charcoal haemofiltration appears to be an excellent treatment of methotrexate intoxication.