The Cree Indians used sweet flag for medicinal purposes, primarily as an analgesic for toothaches or headaches, a disinfectant for teeth, relief for exhaustion or fatigue, and as a cure for hangovers. Other North American Indians used the plant to treat coughs and diabetes. The Sioux used the whole plant, making aromatic garlands from the leaves and using the roots to make tea to treat bowel pains or placing chewed root on the skin to cure illness. Sweet flag has also been used by the Chinese to reduce swelling and to help relieve constipation. In India, the root was used to cure fevers, asthma, and bronchitis. The ancient Greeks also utilized the plant in many traditional remedies. The root was even mentioned in the Bible (Exodus 30: 22-25) as one of the ingredients of the "holy anointing oil." Despite the plant's rich history, it has been banned by the FDA as a food additive because it has proven to be carcinogenic in laboratory rats.