Introduction and Aims: CFTR, a transmembrane Cl- channel important in regulating intestinal fluid and electrolyte secretion, is implicated in the pathogenesis of a number of intestinal disorders. At physiological concentrations, bile acids, acting via the nuclear receptor, farnesoid X receptor (FXR), inhibit colonic epithelial CFTR expression. Dietary phytochemicals have been reported to have the capacity to modulate FXR signalling. Here, we set out to investigate mechanisms underlying FXR regulation of epithelial CFTR expression, and the potential for therapeutically targeting the receptor with dietary phytochemicals. Methods: Polarised monolayers of T84 colonic epithelial cells were treated with the FXR agonist, GW4064 (5µM), in the absence or presence of a plant phytochemical, designated here as KFS1 (5µM). CFTR and FXR expression were measured by qRT-PCR and immunoblotting. Expression of NF-κB, FOXA1, HNF1A, and CDX2, transcription factors that regulate CFTR expression, were measured by qRT-PCR. Nuclear translocation of NF-κB was measured by immunoblotting. Electrophysiological studies of T84 cells were conducted in Ussing chambers. Studies on human colonic enteroids were carried out with ethical approval from Johns Hopkins University School of Medicine Institutional Review Board, while studies of murine colonic epithelial enteroids were conducted with approval from the Institutional Review Board of the University of California San Diego.  Results: Treatment of T84 monolayers with GW4064 significantly downregulated CFTR mRNA to 0.51 ± 0.06 fold after 12 hrs (n=12;p<0.001) and protein levels to 0.28 ± 0.06 fold after 48 hrs, compared to controls (n=8;p<0.001). Electrophysiological studies in Ussing chambers showed that GW4064 treatment for 48 hrs inhibited Cl- secretory responses to the Ca2+-dependent agonist carbachol (CCh;100mM) and the cAMP-dependent agonist, forskolin (FSK;10mM)  by 79.9 ± 7.5 % and 74.2 ± 8.9 %, respectively. Transcriptomic analysis of human colonic enteroids revealed FXR to be robustly expressed in secretory (crypt-like) cells and that its activation also induced CFTR downregulation. FXR activation did not alter expression or phosphorylation of the p65 subunit of NF-κB, or inhibit its translocation to the nucleus. GW4064 downregulated FOXA1 mRNA expression by 33.2 ± 5.2% after 3 hrs (n=4;p<0.05), but had no effect on HNF1A or CDX2 expression. Treatment with the phytochemical, KFS1 (5 mM;24hrs), upregulated FXR mRNA and protein expression in T84 cells and enhanced GW4064-induced downregulation of CFTR mRNA by 0.28 ± 0.05 fold (n=8; p<0.01) and protein by 0.25 ± 0.11 fold (n=4) after 24 hours. Similarly, KFS1 significantly upregulated FXR mRNA expression 2.3 ± 0.2 fold (n=4;p<0.01) compared to controls in murine colonic epithelial enteroids and enhanced GW4064-induced downregulation of CFTR mRNA 0.5 ± 0.1 fold (n=4;p<0.05) compared to GW4064 alone. Finally, KFS1 enhanced FXR inhibition of agonist-induced Cl- secretory responses across T84 cells mounted in Ussing chambers. Conclusion: FXR regulates colonic epithelial CFTR expression and function by a mechanism which appears independent of NF-κB, but which may involve FOXA1. By virtue of their ability to upregulate FXR expression, and thereby enhance its antisecretory actions, plant extracts containing KFS1 have excellent potential to be developed as targeted nutraceuticals for the treatment and prevention of intestinal disease.