Elamin and colleagues in this issue report that acetaldehyde activates Snail, a transcription factor involved in epithelial-to-mesenchymal transition, in an intestinal epithelium. Snail mediates acetaldehyde-induced tight junction disruption and increase in paracellular permeability. Results of this study and other previous studies raise several important questions. This commentary addresses these questions by discussing the acetaldehyde concentration in colon, disruption of epical junctional complexes in the intestinal epithelium by acetaldehyde, and the consequence of long-term exposure to acetaldehyde on colonic epithelial regeneration, carcinogenesis, and metastases. The precise role of acetaldehyde in colonic epithelial modifications and promotion of colorectal cancers still remains to be understood.