Toxicometabolomics of urinary biomarkers for human gastric cancer in a mouse model was investigated using (1)H-nuclear magnetic resonance (NMR) spectroscopy. A human gastric adenocarcinoma cell line (1 × 10(7) cells/ml) was grafted onto the skin of the back of intact male BALB/c-nu/nu mice. After the xenografted tumors developed, urine was collected and analyzed for endogenous metabolites. Global profiling combined with principal components analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and orthogonal projections to latent squares-discriminant analysis (OPLS-DA) showed distinct separation of clusters between control and tumor-bearing mice. Targeted profiling revealed significant changes in trimethylamine oxide (TMAO), 3-indoxylsulfate, hippurate, and citrate levels in mice carrying human gastric cancer cells compared to normal mice. The levels of TMAO (0.41-fold) and hippurate (0.26-fold) in tumor-bearing mice were significantly decreased, whereas the levels of 3-indoxylsulfate (3.39-fold), 2-oxoglutarate (2.32-fold), and citrate (1.9-fold) were significantly increased in urine samples of tumor-bearing mice. Data suggest that TMAO, hippurate, 3-indoxylsulfate, 2-oxoglutarate, and citrate may serve as useful urinary biomarkers for gastric tumorigenesis in a mouse model.