St. John's Wort Extract 300mg 180 tabs, Planetary HerbalsSt. John's Wort Extract Standardized Herbal Supplement Standardized to 0. 3% Hypericin for Emotional Well Being This standardized St. John's wort preparation is based on modern clinical studies, which suggest that 900 mg of St. John's wort extract, standardized to 0. 3% hypericin, is effective for promoting mental well being. Modern Research of St. John's wort St. John's wort, in use since the middle ages, is native to Europe but is now found