Ethnopharmacological relevanceGynura japonica (Thunb.) Juel is often confused with the non-pyrrolizidine alkaloid-producing herbs, Tu-San-Qi (Sedum aizoon L.) and San-Qi (Panax notoginseng L.), due to similarities in name, appearance, and medicinal use. It contains pyrrolizidine alkaloids, which cause over 50% of cases of hepatic sinus obstruction syndrome. However, the mechanisms underlying G. japonica-induced hepatotoxicity remain poorly understood. Aim of the studyIn this study, we aimed to investigate the toxic effects of a G. japonica decoction on liver and Buffalo rat liver (BRL) cells and elucidate the associated mechanisms. Materials and methodsThis study employed G. japonica decoction and examined its effects on liver function and tissue damage in Sprague–Dawley rats. Bioinformatics analysis was employed to identify gene expression and enriched pathways related to hepatotoxicity. Laser scanning confocal microscopy and flow cytometric annexin V/PI labeling assays were utilized to observe apoptosis in BRL cells induced by G. japonica. Transmission electron microscopy and JC-1 staining were used to determine the effects of G. japonica on mitochondrial ultrastructure and membrane potential in BRL cells. The bicinchoninic acid method and enzyme-linked immunosorbent assays were used to detect the expression of apoptosis-related proteins and caspase-3 activity, respectively. ResultsComparisons of body weight, liver histopathology, and serum liver function-related indices in rats, t showed that exposure to G. japonica may cause liver damage. Bioinformatics analysis indicated that hepatotoxicity might be related to apoptotic signaling pathways, the positive regulation of programmed cell death, and responses to toxic substances. BRL cells exposed to the G. japonica decoction exhibited mid-to late-stage apoptosis and necrosis, along with alterations in mitochondrial morphology and membrane potential. Furthermore, expression of cytochrome C (Cyt C) and pro-apoptotic proteins was increased, anti-apoptotic proteins decreased, and caspase-3 activity elevated. ConclusionsThese findings indicate that G. japonica-induced hepatotoxicity involves the activation of mitochondria-mediated apoptosis. Our research enhances the scientific and theoretical foundation for clinical therapy and improves public awareness of the potential toxicity of herbal remedies.