The grape seed extract includes flavonoids, which have antioxidant properties, used to lower the levels of LDLs or bad cholesterol, relax blood vessels, and reduce the risk of coronary heart disease. The antioxidants in grape extract help to prevent heart disease and have other potentially helpful effects. Grape seed extract decreases inflammation and has astringent effects. grape seed extract can bring tissue together, which could benefit stop bleeding and diarrhea.