3-Oxo-5β-cholanoic acid (Dehydrolithocholic acid), a bile acid metabolite, inhibits the diferentiation of TH17 cells by directly binding to the key transcription factor RORγt (K_d=1.13 μM)^[1]. In Vitro: Treatment with 3-Oxo-5β-cholanoic acid significantly reduced the activity of the RORγt reporter. These data suggest that 3-Oxo-5β-cholanoic acid probably inhibits TH17 cell differentiation by physically interacting with RORγt, and inhibiting its transcriptional activity^[1]. In Vivo: 3-Oxo-5β-cholanoic acid (Dehydrolithocholic acid) (0.3% (w/w); p.o.; for 1 week) significantly reduces the percentage of ileal TH17 cells^[1].