An analysis of the gut microbiota of 453 healthy subjects aged 0-104 found that the composition of the gut microbiota could fit in distinct age groups. Fecal metabolites were examined in a study of elderly people in order to investigate the role of gut microbiota. CE-TOF-MS was used to analyze fecal metabolites in 16 elderly patients who were into an age-matched cluster (E-GM) and another 16 elderly patients who were into an age-mismatched cluster (A-GM). The 8 metabolites were different between the groups: the A-GM group was enhanced with cholic acid and taurocholic acid while the E-GM group was enhanced with choline, trimethylamine (TMA), N8-acetylspermidine, propionic acid, 2-hydroxy-4-methyl valeric acid, and 5-methylcytosine. Metabolites (choline, TMA, N8-acetylspermidine) that increased in the E-GM group were found as age-related diseases such as arteriosclerosis and colorectal cancer. The number of various species of Proteobacteria, called TMA-producing bacteria, seemed to be related to fecal TMA levels and was escalated in the E-GM group. The study showed that these metabolites from elderly feces suppressed the tight junctions in normal cells and triggered the inflammatory cytokines in cancerous cells. Metabolites produced by the elderly gut microbiota may contribute to intestinal and systemic homeostasis, as well as being eligible for treatment of aging-related maladies.