DO NOT USE AT ALL. Chenopodium Ambrosioides. This plant is closely related to the parent plant of American wormseed oil. The latter is distilled from Chenopodium Ambrosioldes, var. anthelminthicum. See Wormseed Oil, American. This oil is by far the most important of the two. Chenopodium Ambrosioides is a plant similar to the American wormwood. It grows wild in Brazil and Mexico and it is cultivated in Brazil, India, and Indonesia. Smaller quantities are harvested in France, Central and Eastern Europe. The essential oil is steam distilled from the dried plant which is harvested just before the flowerbuds open. At that moment the essential oil will have the highest content of Ascaridol and related therapeutic ingredients. The oil is used exclusively in medicine as a specific anthelminthicum.