In this study, Nakajima et al., compared the 2D and 3D in vitro gut models. They successfully mimicked the dextran sodium sulfate-induced epithelial barrier dysfunction as a trigger phenomenon of gut inflammation in the 3D gut model. The integrity of the epithelium and phenotypic analysis of the intestinal physiological functions in the simple and reproducible 3D gut model will allow for a drug screeningsystem for assessing the effects on the functions of the gut epithelium from the lumen side.