It is suggested that colorectal cancer might be prevented by changes in diet, and vegetable consumption has been demonstrated to have a protective effect. Until now, little is known about the effects of vegetable consumption at the proteome level. Therefore, the effect of increased vegetable intake on the protein expression in the colonic mucosa of healthy mice was studied. Aim was to identify the proteins that are differentially expressed by increased vegetable consumption and to discriminate their possible role in the protection against colorectal cancer. Mice were fed four different vegetable diets, which was followed by analysis of total cellular protein from colonic mucosal cells by a combination of 2-DE and MS. We found 30 proteins that were differentially expressed in one or more diets as compared to the control diet. Six could be identified by MALDI-TOF MS: myosin regulatory light chain 2, carbonic anhydrase I, high-mobility group protein 1, pancreatitis-associated protein 3, glyceraldehyde-3-phosphate dehydrogenase and ATP synthase oligomycin sensitivity conferral protein. Alterations in the levels of these proteins agree with a role in the protection against colon cancer. We conclude that these proteins are suitable markers for the health effect of food on cancer. The observed altered protein levels therefore provide support for the protective effects of vegetables against colorectal cancer.