In the treatment of non Hodgkin’s lymphoma fundamental advances were made. More than 70 % child patients can be cured. Intrathecally administered (i.t.) methotrexate, cytosine arabinoside and predni- sone are nowadays standard constituents of treatment and prevention of affections of the CNS. From clinical practice and occasional papers in the professional literature it is apparent that even fatal erroneous i.t. administration of the drug cannot be ruled out. Most frequently the mistaken adminis- tration of vincristine is mentioned. In the submitted case-history the authors draw attention to possible tragic use of actinomycin D (AMD) instead of methotrexate (MTX). To a five-year-old patient, treated for three months by the German protocol BMF 90, on account of T lymphoblastic high risk NHL instead of methotrexate actinomycin D was administered. One hour later the neurosurgeons started ventricu- lolumbar drainage with saline. Subsequently the authors administered after consultation with toxico- logical centres large doses of corticoids, ascorbic acid and administered sodium thiosulphate by the i.v. route. The patient developed after AMD paraplegia of the lower extremities and loss of continence despite microsurgical removal of an arachnoidal cyst. Although treatment of the primary disease was prematurely terminated, the patient has been for two years in complete remission.

        Key words: actinomycin D, intrathecal administration, ventriculolumbar lavage, methotrexate, exter- nal neurolysis of the caudal roots