BACKGROUND Diosgenin, a phytosteroid sapogenin, has anti-inflammatory properties shown to reduce myocardial ischemia-reperfusion injury (MIRI). However, the specific mechanism by which this is achieved is not clear. This study investigated the protective effects of diosgenin on myocardial ischemia/reperfusion (I/R) and the potential anti-inflammatory mechanisms. MATERIAL AND METHODS Healthy adult male SD rats, body weight (b.w.) 250-280 g, were used to model ischemia-reperfusion injury (IRI) and were administered diosgenin (50 mg/kg and 100 mg/kg b.w.) intragastrically for 4 consecutive weeks before surgery. The left anterior descending artery (LAD) was ligated to induce myocardial ischemia for 30 min and reperfusion for 30 min, 60 min, and 120 min while relevant indicators were detected. RESULTS Both 50 mg and 100 mg diosgenin oral administration increased left ventricular developed pressure (LVDP) and maximum changing rate of ventricular pressure (±dp/dtmax), decreased left ventricular end-diastolic pressure (LVEDP), and myocardial enzyme markers. TTC staining suggested that diosgenin reduced myocardial infarct size in the rat model. Pathological results showed that myocardial ischemia and inflammation were alleviated by diosgenin. In addition, the increased expression of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) in serum, and myeloperoxidase (MPO) in myocardium were significantly suppressed by diosgenin administration. Diosgenin further inhibited the phosphorylation of transcription factor NF-κB and modulated the expression of downstream inflammatory cytokines by regulating the activation of p38-MAPK and JNK pathways. CONCLUSIONS Results demonstrate diosgenin plays an anti-inflammatory role in the protection of MIRI through regulation of p38-MAPK and JNK pathways and phosphorylation of NF-κB.