The leaves, fruit, and juice of grapes have all been used medicinally throughout history, but only the extract has exhibited pronounced therapeutic effects by way of its antioxidant properites.  This antioxidant effect serves to reduce the buildup of the so-called "bad cholesterol" that clogs the arteries and leads to stroke and heart attacks.

Proanthocyanidin, a flavonoid compound found in grape seeds, strengthens the tiny blood vessels called capillaries.  It also helps prevent unstable oxygen molecules called free radicals from getting out of control and doing harm to the body.