Hellebore flower (Helleborus sp.). Close-up showing reprodutive organs including stamens (yellow) and carpels (purple). This plant is poisonous, but preparations made from it have been used in herbal medicine for centuries. It has been used as a purgative and an anthelmintic (killing intestinal worms). When applied to the skin it has a strong irritant action. Tinctures of hellebore have also been used to treat hysteria.