Evergreen plants. A common polypody fern (Polypodium vulgare) is at left and a stinking hellebore plant (Helleborus foetidus) is at right. The stinking hellebore plant is poisonous. Both plants are used in herbal medicine. The polypody fern is used to treat hepatitis, jaundice, pleurisy, hives, sore throats and stomach aches. Stinking hellebore is used to reduce blood pressure and in the treatment of headaches, psychic disorders, enteritis and spasms.