Wormwood essential oil is steam-distilled from the wild-crafted, dried leaves and flowers of a plant native to central and southern Europe. Its odor is green, warm and deep. It has been used in the treatment of worm infestations such as roundworm and pinworm. It has also been used as a digestive tonic to treat loss of appetite and indigestion. It has a high thujone content and must be used with caution.