Background and Purpose-Oxidative stress is known to be involved in ischemic stroke. Intense interest is drawn to the therapeutic potential of Chinese herbs on ischemic stroke because many of them contain antioxidant properties. Leonurine, 1 of the active compounds from purified Herba Leonuri, was studied to evaluate its possible therapeutic effects on ischemic stroke. Method-Middle cerebral artery occlusion was selected as our model of study. The animals were pretreated with Leonurine orally for 7 days and the surgery was done. One day after surgery, 2,3,5-triphenyltetrazolium chloride staining and neurological deficit score were carried out to evaluate the functional outcome of animals, whereas levels of superoxide dismutase, glutathione peroxidase, and malondialdehyde were analyzed for oxidative stress analysis. For mitochondrial studies, 3 hours after surgery, mitochondria were isolated for analysis of reactive oxygen species production, adenosine triphosphate biosynthesis, oxygen consumption, and respiratory control ratio value. Result-In in vivo experiments, Leonurine pretreatment reduced infarct volume, improved neurological deficit in stroke groups, increased activities of antioxidant enzymes superoxide dismutase and glutathione peroxidase, and decreased levels from the lipid peroxidation marker malondialdehyde. In terms of mitochondrial modulation, Leonurine inhibited mitochondrial reactive oxygen species production and adenosine triphosphate biosynthesis. Animal studies also demonstrated that the mitochondrial function and redox state were restored by Leonurine treatment. Conclusions-Leonurine has neuroprotective effects and carries a therapeutic potential of stroke prevention. (Stroke.