Dao Dou (Zi)

Dao Dou Zi (刀豆子), or simply Dao Dou, is the mature dried seed of Canavalia gladiata (Jacq.) DC. (Fabaceae), the sword bean, a vigorous twining annual or short-lived perennial legume cultivated across southern China and Southeast Asia. The plant climbs 4–10 meters with trifoliolate leaves and pale violet to white papilionaceous flowers, producing large, flattened, scimitar-shaped pods 20–35 cm long that contain several large, smooth, reddish to pinkish seeds about 2–3 cm long. The seeds are harvested at maturity, shelled, and dried. In TCM, Dao Dou Zi is classified as sweet and warm, entering the Stomach and Kidney channels, and is used to warm the middle, descend rebellious qi, stop hiccup and vomiting, and tonify the Kidneys, with classical indications including stubborn hiccup, lumbar weakness, and cold-deficient stomach.