Enteropathogenic Escherichia coli (EPEC) adhere in vivo to enterocytes. This adhesion capacity can be obtained in vitro with Hep-2 cells on which a characteristic localized adherence (LA) is observed. We studied the effect of subinhibitory concentrations (SIC) of nifurzide, a nitrofurane derivative, on this bacterial adherence phenomenon. Three EPEC strains are used: 11201 (026 serogroup), 7958 (0128) and 7836 (0142). Various SIC (MIC/2; MIC/4;...; MIC/32) were added either to the culture medium of bacteria or to the Eagle medium in which bacteria and Hep-2 cells were mixed during the adhesion experiments. In each case an adhesion index is determined. Nifurzide strongly inhibits the adherence capacity of the three strains when concentrations ranging from MIC/2 to MIC/16 where added in both culture media. On the other hand three other nitrofurane derivatives which have no antibacterial effect did not inhibit adherence. The mechanism of the adherence inhibition by nifurzide is discussed.