Abstract: This experiment aimed to verifying the effect of capsaicinoids on the cecal fermentation environment by in vitro. Adding 0. 05%, 0. 1%, 0. 15% capsaicinoids in cecum content liquids, the pH, free ammonia, short-chain fatty acids (SCFAs) and the amounts of Bifidobacterium, Lactobacillus, E. col i. in cecal content liquids after incubating 10h were mensurated. Compared with control liquid, pH, free ammonia concentration and the amounts of E. col i. were increased, and SCFAs content, the amount of Bifidobacteria and Lactobacillus were decreased in cecal content liquids adding capsaicinoids. These results were dose-depended manner of capsaicinoids. The current results indicate that capsaicinoids have latent harm to intestinal fermentation environment.