Don't wait until a sense of urgency sets in-give your head the support it needs to maintain healthy blood flow to the brain with Swanson Superior Herbs Feverfew Extract. For centuries European herbalists have used feverfew for a wide range of health applications. In modern times it has gained prominence for its ability to support cerebral blood vessel tone and promote healthy circulation to the brain. Our Feverfew Extract is standardized to 0.5% parthenolide concentration for guaranteed herbal potency in each capsule.