Enterohaemorrhagic Escherichia coli (EHEC), particularly of serotype O157:H7, are the most common cause of haemorrhagic colitis (HC) which can lead to life-threatening haemolytic uraemic syndrome (HUS) in humans. Verotoxins (VT; or shiga-like toxins) are major virulence factors and are key determinants in the patho-physiology of EHEC infections in humans. Cattle are an important reservoir host for EHEC in which infection occurs asymptomatically. Consequently the significance of virulence determinants, including VT, in the bovine host is obscure. Initial work identified potential contribution of VTs to bacterium-host interactions and this investigation aimed to characterise roles of VT in colonization of bovine intestinal epithelium by EHEC. For this, adherence of a panel of wild-type and mutant (VT- negative) EHEC strains to primary epithelial cells from the most terminal part of rectum (the principal site of EHEC colonization in cattle) was conducted (tissue obtained from the abattoir). Carriage of VT was associated with greater adherence to epithelium as demonstrated by higher capacity to form micro-colonies. Pre-treatment of cells with VT produced a similar phenotype. VT exhibited further effects on epithelium through reduction of secretion of IL-8, an important epithelial inflammatory mediator. VT of EHEC therefore do not show classic cytotoxicity for bovine intestinal epithelium but do exert pleiotropic effects on these cells, by modifying epithelial physiology hence enabling EHEC colonisation.