Cotton grass root is also known as leucaena leucocephala root. It has the effect of cooling the blood and stopping bleeding (cooling and moisturizing the blood to prevent bleeding), and is mainly used for treating hemorrhagic syndrome and edema. Cold in nature and sweet in flavor, leucaena root belongs to the lung, stomach and bladder meridians. It has the efficacy of cooling the blood to stop bleeding, clearing heat and diuresis, and clearing heat from the lung and stomach. Clinically, it is mainly used in the treatment of epistaxis (nosebleed), hemoptysis, hematochezia, hemorrhagic gonorrhea (the appearance of blood in the urine accompanied by pain) and other bleeding syndromes, heat-poisonous gonorrhea (increased frequency of urination, dribbling and astringent pain), oedema, jaundice due to dampness-heat, gastric-heat, vomiting and lung-heat coughing and wheezing. It can also be used externally by pounding the juice. It is forbidden to take Bai Mao Gen for those who are weak and cold in the spleen and stomach (spleen and stomach weak and cold), and those who have excessive urination without thirst. The root is usually harvested in the spring or fall, and the above-ground parts and scaly leaf sheaths are removed and used fresh or tied and dried in the sun. The root is prepared by taking the original herb, removing impurities, washing, moistening, cutting and drying. After concocting, it is stored in dry containers and placed in ventilated dry places. This medicine should be taken under the guidance of a traditional Chinese medicine practitioner, and should not be used blindly on one’s own to avoid delaying the condition.