Certain gut microbes and their metabolites contribute to the progression of benign colorectal adenoma (CRA) into colorectal cancer (CRC), but the specific microbes, metabolites, and mechanisms involved are unclear. To learn more, researchers recently analyzed stool samples from patients with CRA or CRC and normal control (NC) subjects. The levels of certain stool metabolites significantly differed among the groups. For example, myristic acid and norvaline became more abundant with progression from health to CRC. The CRC-associated metabolites were largely branched- chain amino acids and aromatic amino acids and were involved in aminoacyl-tRNA biosynthesis pathways. A metabolite “signature” distinguished CRC samples from NC samples and CRC samples from CRA samples and the relationships among CRC-related metabolites and gut bacteria differed in the different sample types. Integrating bacterial abundance into the metabolite signature improved the signature’s ability to differentiate among NC, CRA, and CRC samples. Although confirmation is needed, the results emphasize the importance of microbial metabolites in CRC development and suggest that fecal metabolites can be assessed alongside bacteria to aid in early, noninvasive diagnosis of CRC.