Dietary Supplement. Premium extract. 0.7% Parthenolide. Health & longevity through the healing power of nature-that's what it means to trust the leaf. Feverfew Extract (Tanacetum parthenium) is standardized to 0.7% Parthenolide, the herb's key active. Questions? Call 1-800-9-Nature or visit naturesway.com. Our Feverfew extract is carefully tested and produced to superior quality standards. Satisfaction guaranteed.