Brain ischemia and treatment are one of the important topics in neurological science. Free oxygen radicals and inflammation formed after ischemia are accepted as the most important causes of damage. Currently, there are studies on many chemopreventive agents to prevent cerebral ischemia damage. Our aim is to research the preventive effect of the active ingredient in genistein, previously unstudied, on oxidative damage in cerebral ischemia. Rats were randomly divided into three groups: control group (no medication or surgical procedure), ischemia group, and artery ischemia+genistein group, sacrificed at 24 h after ischemia. The harvested brain tissue from the right hemisphere was investigated histopathologically and for tissue biochemistry. Superoxide dismutase and nuclear respiratory factor 1 values decreased after ischemia and they increased after genistein treatment, while increased malondialdehyde levels after ischemia reduced after treatment. Apoptosis-related cysteine peptidase caspase-3 and caspase-9 values increased after ischemia, but reduced after treatment. Our study revealed that genistein treatment in cerebral ischemia reduced oxidative stress and neuronal degeneration. We believe that genistein treatment may be an alternative treatment method.