BACKGROUND: Renal interstitial fibrosis (RIF) is the primary pathological progression in chronic kidney disease (CKD). Given the constraints related to cost and adverse effects of current treatments, it is crucial to explore novel and efficacious therapeutic strategies. The purpose of this study was to elucidate the potential of Jiawei Danggui Buxue Decoction (JDBD) to reduce apoptosis and epithelial-mesenchymal transition (EMT) in RIF by regulating the Janus kinase 2 (JAK2)/Signal Transducer and Activator of Transcription 3 (STAT3) pathway. METHODS: An angiotensin II (Ang II)-induced HK-2 cells model and a unilateral ureteral obstruction (UUO) animal model were employed to replicate the RIF model. A total of 48 male Wistar rats (weighing 200-220g) were acclimated for 1 week and then randomly divided into 6 groups (sham operation, UUO, Losartan potassium tablets, and three JDBD dosage groups: high, medium, and low, n=8). After the acclimatization period, UUO models were established in 40 rats through surgery, excluding the sham operation group. Each group received the corresponding drug via gavage for 2 weeks. After 2 weeks, rats were anesthetized, and tissues were collected for subsequent analysis. Renal function tests and histological stains were used to evaluate renal damage and histopathological alterations in rats. Cell viability was examined using the CCK-8 assay. Apoptosis was identified through the utilization of flow cytometry and assessment of mitochondrial membrane potential, along with other techniques. We identified and examined the expression of EMT and extracellular matrix (ECM)-related factors, as well as the JAK2/STAT3 pathway. RESULTS: In vivo experiments indicated that JDBD effectively reduced renal dysfunction in UUO rats, ameliorated pathological changes in renal tissues, and significantly modulated the JAK2/STAT3 signaling pathway to inhibit EMT and apoptosis, thereby reducing ECM deposition. Furthermore, JDBD markedly increased the survival rate of Ang II-treated HK-2 cells and reduced apoptosis. The in vitro experimental results further confirmed that JDBD ameliorates RIF by regulating the JAK2/STAT3 pathway. CONCLUSION: JDBD exhibits anti-apoptotic and EMT-inhibiting functions in RIF, potentially mediated by targeting and inhibiting JAK2/STAT3 signaling transduction.