〔Abstract〕 Objective To investigate the effects of Cyp4 a14 gene, Malondialdehyde(MDA) and the related inflammatory factors on intestinal mucosal oxidative stress in mice. Methods Male mice of Cyp4 a14+/+and Cyp4 a14-/-were selected and randomly divided into 4 groups: Cyp4 a14+/+control group, Cyp4 a14+/+DSS group, Cyp4 a14-/-control group, Cyp4 a14-/-DSS group. Both control groups were given cleaning water to drink for 6 days, and both DSS groups were given 3.0% DSS solution to drink for 6 days. Colon inflammation was comprehensive evaluated by changes in constitution/quantity, disease activity index(DAI), colonic length and HE staining. The mRNA levels of pro-inflammation cytokines(IL-1β and TNF-α) were quantified by Real-time PCR. The concentration of MDA in serum was measured by biochemical method to evaluate the degree of oxidative stress. Results There was no signs of enteritis in the two control groups, Cyp4 a14-/-DSS group showed mild enteritis, while Cyp4 a14+/+DSS group showed severe enteritis. The expressions of IL-1β and TNF-α in the colon increased both in Cyp4 a14+/+DSS group and Cyp4 a14-/-DSS group, and Cyp4 a14+/+DSS group increased more significant than Cyp4 a14-/-DSS group. The serum concentration of MDA in Cyp4 a14-/-control group decreased compared with that in Cyp4 a14+/+control group. Compared with the two control groups, serum MDA concentrations both increased in the Cyp4 a14+/+DSS group and the Cyp4 a14-/-DSS group, especially in the Cyp4 a14+/+DSS group, There were differences among the four groups(F=573.233,P<0.001). Conclusion Lipid peroxides MDA decreases in colon tissues of mouse knockout of Cyp4 a14 gene, and the sensitivity to DSS-induced colitis decreases, suggesting that Cyp4 a14 gene may be a promoter of oxidative stress in colon tissues of mice.