Intestinal cytochrome P450 enzymes (P450s) play an essential role in the first‐pass metabolism of orally administered drugs and other xenobiotics. The expression of intestinal P450s can be regulated by many environmental or pathophysiological factors, including tissue inflammation. In the present study, we have explored the impact of inflammation on the expression of intestinal P450s in a mouse model of dextran sulfate sodium (DSS)‐induced colitis. Several P450 enzymes, including CYP1A1, CYP2B, CYP2C, and CYP3A, were downregulated at both mRNA and protein levels in mice treated with DSS (2.5% in drink water for 7 days), along with increased cytokine levels in colon epithelium. The impact of this downregulation on P450‐mediated drug metabolism was also studied. In addition, the expression of several nuclear receptors that are potentially involved in the regulation of intestinal P450 expression was compared between control and DSS‐treated groups. Whereas no difference was detected in the expression of PXR, CAR, or FXR, the expression of several FXR target genes was significantly decreased by the DSS treatment. Interestingly, the expression of VDR and its target genes was also suppressed by the DSS treatment. Thus, both FXR and VDR may be involved in the downregulation of intestinal P450s in DSS‐induced colitis. Further studies on the mechanism of P450 downregulation in the intestine by DSS‐induced colitis are warranted.Support or Funding InformationSupported in part by NIH grant GM082978