Acute myocardial infarction is one of the major leading causes for heart failure, which can lead to the irreversible loss of cardiomyocytes and impaired cardiac function. Hence, the efficient therapeutic agents are still urgent. Our study aimed to explore the role of a natural isoquinoline alkaloid, palmatine, in an acute myocardial infarction mouse model. In this study, intragastric administrated palmatine significantly enhanced left ventricle ejection fraction and left ventricle end-systolic of infarcted mice heart. Meanwhile, palmatine administration partially recovered myocardial structure and attenuated the cardiac fibrosis and infiltration of inflammatory cells. In addition, the usage of palmatine further enhanced the increased transforming growth factor (TGF)-beta1 level, reduced the elevated tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta level in the myocardium of acute myocardial infarction–induced mice, as well as elevated the reduced superoxide dismutase production and inhibited the increased malondialdehyde secretion in infarcted myocardium of mice. Meanwhile, acute myocardial infarction led the significant upregulation of Bcl-2-associated X and downregulation of B-cell lymphoma-2 in the myocardium, and palmatine administration statistically enabled to recover the expression changes of these two apoptosis-related proteins. Moreover, palmatine administration obviously elevated the expression levels of phosphorylated AMP-activated protein kinase and nuclear factor erythroid 2–related factor 2 in the myocardium of acute myocardial infarction–induced mice. In a word, our study indicated that palmatine could protect infarcted myocardium of mice from apoptosis, inflammation, and oxidative stress. Our results suggested that palmatine might be a novel therapeutic agent for acute myocardial infarction. Graphical Abstract: [Figure not available: see fulltext.] © 2022, The Author(s).