St. John's Wort Average Plant extracts No known benefits St. John's Wort description Plant that contains several components that can cause a negative reaction on skin when it is exposed to sunlight; however, this is a bigger concern when St. John’s wort is taken orally. Like most plants, it’s a rich source of antioxidants. Related ingredients: Hypericum Perforatum Extract Hypericum Extract Hypericum Perforatum Flower/Leaf/Stem Extract