Authors refer to a not much known cause of ARDS as an adverse reaction in treatment with betalactam antibiotics. In 1997 - 1998 691 children were treated in our ICU. We found in 25 cases elevated level of antibodies against betalactam antibiotics. Indication for examination of antibody levels were an X-ray picture of wet lung, concurrent administration of betalactam antibiotics and sometimes a positive allergic history. Antibodies were determined by the method of indirect haemaglutination with a level of 1 : 320 and more being a positive finding. In these cases antibiotic treatment was changed to other antibiotics. We found regression of the X-ray finding in 20 cases, 5 children died. Histological investigation for evaluation of immunocomplexes C3 and IgG in the alveolar wall was made immediately post mortem. Imunofluorescent findings were positive in 4 cases. The authors recommend in case of deterioration of pulmonary changes to evaluate antibody levels and to replace betalactam antibiotics by other antibiotics.

        Key words: betalactam antibiotics, level of antibodies against betalactam antibiotics, adverse effect of antibio-