BACKGROUND: The role of NLR family pyrin domain containing 3 (NLRP3) in post-endoscopic submucosal dissection (ESD) esophageal stricture remains incompletely understood. The effect of celastrol (CEL) on the prevention of esophageal strictures has not yet been investigated. AIM: To explore the effect of CEL on the prevention of esophageal stricture in rats. METHODS: NLRP3, interleukin (IL)-1β, and IL-18 mRNA levels were measured in patients' tissues after esophageal ESD. NLRP3 expression in esophageal fibroblasts was determined using immunohistochemistry and immunofluorescence staining. Lentiviral transfection was used to induce NLRP3 overexpression and thioredoxin reductase 1 (TXNRD1) silencing. The CCK8 assay was used to determine the optimal CEL concentration. Reactive oxygen species (ROS) generation was detected via fluorescence and flow cytometry. Masson's trichrome staining and barium esophagography were performed to assess collagen deposition and esophageal stenosis. RESULTS: The mRNA levels of NLRP3 and IL-1β were higher in human tissues from the ESD resection bed than in normal esophageal mucosa. NLRP3 overexpression in primary rat esophageal fibroblasts led to high collagen 1 expression. Thus, NLRP3 participated in esophageal inflammation and tissue repair after ESD. Comparable to prednisolone, CEL significantly inhibited NLRP3 activation in vitro and in vivo, and esophageal strictures were markedly alleviated. Mechanistically, CEL upregulated TXNRD1 expression and reduced ROS production, thereby inhibiting NLRP3 expression. This effect was reversed by TXNRD1 silencing. Furthermore, TXNRD1 interacted with NLRP3 and promoted its ubiquitination. CONCLUSION: CEL is a promising alternative therapeutic agent for the prevention of post-ESD esophageal strictures.