Colorectal cancer is the second leading cause of cancerrelated deaths in the United States. Although noninvasive fecal blood tests are widely used for the early detection of colorectal neoplasia, these tests have limited sensitivity and specificity. Metabolomics can be used to identify and quantify small molecules. In this study, metabolic profiling of feces was evaluated as a potential noninvasive approach to identify biomarkers of colorectal carcinogenesis. The cover image shows time-dependent effect size differences in metabolite levels in feces from colon tumor-bearing mice vs. healthy mice. Feces were analyzed three, five, and seven weeks following six weekly injections of azoxymethane, a colon carcinogen, or saline. The levels of fecal metabolites progressively change as tumor burden increases. Metabolomic profiling of feces represents a promising method to noninvasively detect colorectal tumors. See article by Montrose et al. (beginning on page 1358) for more information.