not-yet-known not-yet-known not-yet-known unknown Background: We have previously described that 87,6 % of children with juvenile colorectal polyp (JCP) from La Plata Children’s Hospital are sensitized to food allergens. Tissues of JCP are characterized by type 2 inflammation and the abundant presence of active sites of IgE synthesis. Objective: The aim of this work was to study a potential link between polyps and gut microbiota dysbiosis. Methods : We characterized bacterial populations in feces of food allergen-sensitized children with JCP, feces from healthy children and those associated with JCP tissues. Microbial diversity and composition were evaluated using next generation sequencing of the amplified 16S rRNA gene V3-V4 hypervariable region. Results: The principal component analysis applied to β-diversity discriminated well among sample groups. The taxonomic characterization of the bacterial communities in stool samples from food-sensitized children showed a reduced abundance of Bacteroidetes (Bacteroides) and, at the genera and species levels, an increased number of Mediterraneibacter faecis, Prevotella copri, Catenibacterium , and Prevotella hominis , Sutterella wadsworthensis and Phascolarctobacterium A succinatutens compared to feces of healthy children. We found that the microbiome associated with the polyp tissues was enriched in inflammation- and colorectal cancer associated bacteria, including Fusobacterium, Escherichia and Corynebacterium, with elevated levels of Escherichia fergussoni , Akkermansia muciniphila and Enterocloster . Conclusion: Our study highlights differences in bacterial diversity between food sensitized and healthy children’s feces, and that associated with the polyps. This is the first comprehensive description of JCP microbiota in food sensitized patients and may reveal mechanisms of allergic inflammation and polyp formation, underscoring the importance of monitoring for potential malignant lesions.