ETHNOPHARMACOLOGICAL RELEVANCE: Changyanning tablets (CYN) are a marketed traditional Chinese medicine composed of Diijincao (Euphorbia humifusa Willd.), Jinmaoercao (Hedyotis chrysotricha (Palib.) Merr.), Zhangshugen (root of Cinnamomum camphora (L.) J.Presl), Xiangru (Elsholtzia ciliate (Thunb.) Hyl.), and Fengxiangshuye (leaf of Liquidambar formosana Hance). They possess the functions of clearing heat, removing dampness, and regulating qi. CYN is used for the treatment of diarrhea and dysentery caused by damp heat in the large intestine, with symptoms such as diarrhea, or stools with pus and blood, tenesmus, abdominal pain and distension, acute and chronic gastroenteritis, diarrhea, bacterial diarrhea, and indigestion in children. AIM OF THE STUDY: This study aims to explore the intervention effects of CYN on Crohn's disease (CD) and its potential mechanisms. MATERIALS AND METHODS: The therapeutic effect and potential mechanism of CYN on CD were investigated based on the 2,4,6-Trinitrobenzenesulfonic acid solution (TNBS)-induced rat model. In vivo and in vitro experiments confirmed that CYN can alleviate CD by inhibiting GPX4-mediated ferroptosis. siRNA was used to knock down GPX4 for reverse validation. Finally, active components of CYN inhibiting ferroptosis were identified using UPLC-MS and the RSL3-induced HCoEpiC ferroptosis cell model. RESULTS: CYN significantly improved ferroptosis-related indicators (GSH, MDA, GPX4, and SLC7A11) in the colons of TNBS-induced CD rats. Screening with three ferroptosis inducers (RSL3, FINO2, and erastin) revealed that CYN was most effective against RSL3 (a ferroptosis inducer targeting GPX4)-induced apoptosis. Subsequently, the resistance effect of CYN on RSL3-induced ferroptosis was confirmed in vitro. Further in vivo experiments showed that CYN alleviated local CD-like intestinal injury induced by RSL3 enema. siRNA knockdown of GPX4 in HCoEpiC cells further validated GPX4 as major target of CYN in inhibiting ferroptosis. Finally, UPLC-MS and in vitro experiments identified rutin, rosmarinic acid, and kaempferol-3-O-sophoroside as key active components of CYN for inhibiting ferroptosis. CONCLUSIONS: CYN alleviates CD by inhibiting GPX4-mediated ferroptosis, highlighting its clinical potential for treating CD and enhancing the understanding of the pathogenic and therapeutic mechanisms associated with CD.