Colorectal cancer (CC) affects the integrity, permeability and the barrier function of the intestinal cells. Yacon flour (YF) (Smallanthus sonchifolius) is a rich source of prebiotics, fructo‐oligosaccharides (FOS), with potential benefits to intestinal health. Its effect on the CC, however, is still unknown. The objective of this study was to investigate the intestinal effects of YF supplementation in animal model of induced colon cancer. Adult male Wistar rats were divided into groups S (without CC and without YF, n=10), C (with CC and without YF, n=12), Y (without CC and with YF, n=10) and CY (with CC and YF, n=12). Groups C and CY received, subcutaneously, a weekly dose of 25 mg/kg body weight of 1,2‐dimethylhydrazine (DMH) for 5 weeks, followed by eight weeks for CC development. During this period of 13 weeks, all groups received commercial chow. Thereafter, the AIN‐93 M diet was provided, and the Y and CY groups consumed YF in amounts sufficient to provide 7.5% of FOS. After 8 weeks, were determined: intestinal permeability, intraluminal pH, endotoxemia (Lipopolysaccharides ‐ LPS), aberrant crypt foci (ACF), qualitative histology (apical diameter, baseline diameter and crypt depth, beyond the crypts count per field), Secretory IgA (SIgA), and butirate. The data were analyzed by two‐way ANOVA (analysis of variance) followed by Newman‐Keuls test (p <0.05) to evaluate the effect of the CC, YF and the interaction between them. The protocol was approved by the Ethic Committee (CEUA‐UFES#004/2014). Yacon flour exerted beneficial and significant effect on intestinal permeability, given that the urinary excretion of lactulose and mannitol was lower in Y and CY groups compared to control groups (S and C). Furthermore, there was a positive action in reducing the intraluminal pH, the percentage of ACF levels, in addition to increased number and depth of the colonic crypts. There was also a significant increase in butyrate and SIgA secretion in the groups fed YF. However, it was not observed effectiveness of YF on the number of ACF and in LPS. In conclusion, the YF was effective in the modulation of gut health in animal model of colorectal cancer.Support or Funding InformationCNPq ‐ Brazil