Herbal Extract Standardized Maximum Strength Formula to Support Healthy Mood Levels Dietary Supplement 21st Century...for a Healthier Future 100% Vegetarian Formula 21st Century's St. John's Wort Extract (Hypericum perforatum) is a perennial plant found in North America and used for many years as a calming herb. St. Johns Wort Extract contains Hypericin to promote the mind and body. 21st Century's standardized herbal extracts are thoroughly tested to assure quality for maximum benefit.