(Cell 165, 1708–1720; June 16, 2016) Our article investigated the effects of the metabolites produced by gut bacteria on intestinal stem cells and the role of intestinal morphology in mitigating those effects. Part of the study involved the generation of stem cells and colonocytes in vitro. In Figure S4, we characterized these stem cells and colonocytes with immunostaining. In the leftmost and middle images of panel C, we had intended to present micrographs from spheroids enriched in stem cells (leftmost) and in vitro differentiated colonocyte spheroids (middle) derived from colon tissue, as indicated in the original figure legend. However, we mistakenly presented micrographs of spheroids originally derived from small intestinal tissue. To correct the inconsistency introduced between the figure image panels and the legend, we now present below the figure in which the leftmost and middle images of panel C display our micrographs of a colon-derived stem cell spheroid (leftmost panel) and in vitro differentiated colonocyte spheroid (middle panel). The figure has been corrected online, and as the spheroids from both sources show similar polarity and localization of actin and β-catenin, this change does not alter any of our conclusions.