A retrospective case-control study with a small population group revealed that, among clinical signs, vomiting but not diarrhea was significantly associated with the presence of diffusely adhering Escherichia coli (DAEC) in children suffering from gastroenteritidis (P < 0.05). Of the children carrying DAEC strains, those who were F1845 DNA probe positive had a significantly longer hospital stay than those who were F1845 DNA probe negative. We believe that the heterogeneity of DAEC strains is responsible for the discrepant results concerning their involvement in disease and that only some of these strains are really pathogenic for children.