Intestinal mucus glycoproteins extracted from faeces of healthy adult subjects were used as a substratum for bacterial adhesion to investigate the effects of physical, chemical and enzymatic pre-treatments of the bacteria on their adhesion. The strains studied were Lactobacillus acidophilus 1 (LCI, Nestlé), L. rhamnosus strain GG (ATCC 53103), L. rhamnosus LC-705, and L. casei strain Shirota (Yakult, Yakult Ltd). Hereafter the strains are referred to as LA1, LGG, LC-705, and Shirota, respectively. Strains LA1 and LGG adhered greatly whereas the adhesion of strains LC-705 and Shirota to intestinal mucus glycoproteins was low. Adhesion of LA1 and LGG was reduced by boiling, autoclaving and by pepsin and trypsin treatments suggesting that the bacterial protein structures are essential for their adhesion. Treatment in ethanol and in propanol prior to adhesion significantly increased the adhesion of LA1 and LC-705, respectively. Adhesion of Shirota strain was not altered by any of the treatments.