补肝肾，泻恶血
苦酸而平。足厥阴、少阴经药（肝肾），能引诸药下行。酒蒸则甘酸而温，益肝肾，强
筋骨（肝主筋，肾主骨），治腰膝骨痛，足痿筋挛（下行故理足，补肝则筋舒，血行则痛止），
阴痿失溺（筋衰则阴痿，肾虚则失溺），久疟下痢，伤中少气（以土皆补肝肾之功）。
生用，则散恶血，破症结（血行则结散），治心腹诸痛，淋痛尿血（热蓄膀胱、便涩而
痛曰淋。气淋便涩余沥，劳淋房劳即发，冷淋寒战后溲，膏淋便出如膏，石淋精结成石，尿
血即血淋也。鲜色者，心与小肠实热；色瘀者，肾与膀胱虚冷。张子和曰∶石淋乃肝经移热
于胞中，日久熬煎成石，非肾与小肠病也。大法治淋宜通气、清心、平火、利湿。不宜用补，
恐湿热得补增剧也。牛膝，淋证要药，血淋尤宜用之，杜牛膝亦可。又有中气不足致小便不
利者，宜补中益气，经所谓气化则能出是也，忌用淋药通之），经闭产难（下行之效，误用
堕胎），喉痹齿痛（引火下行），痈肿恶疮，金疮伤折（以上皆散恶血之功），出竹木刺（捣
烂罨之即出；纵疮口合，刺犹自出）。然性下行而滑窍，梦遗失精及脾虚下陷，因而腿膝肿
痛者禁用。
出西川及怀庆府，长大肥润者良。下行生用，入滋补药酒浸蒸。恶龟甲。畏白前。忌羊
肉。
Tonifies the Liver and Kidneys, drains evil blood.
Bitter and sour in taste, neutral in nature. It enters the Foot Jueyin (Liver) and Foot Shaoyin (Kidney) meridians (corresponding to the Liver and Kidneys), and has the ability to guide the action of other herbs downward. When steamed with wine, it becomes sweet and sour in taste, and warm in nature, tonifying the Liver and Kidneys, strengthening sinews and bones (the Liver governs sinews, the Kidneys govern bones), treating pain in the lower back and knees, flaccidity of the feet, and tendon spasms (due to its downward action, it regulates the lower limbs; tonifying the Liver relaxes the sinews, and promoting blood circulation stops pain), impotence, and urinary incontinence (sinew degeneration leads to impotence; Kidney deficiency leads to urinary incontinence), chronic malaria, dysentery, damage to the middle jiao with shortness of breath (this is achieved through the merit of tonifying the Liver and Kidneys).
When used raw, it disperses evil blood and breaks masses (when blood circulates freely, stagnation dissipates), treating various pains in the chest and abdomen, strangury with pain, and hematuria (heat accumulating in the Bladder causing difficult and painful urination is called strangury. Qi strangury presents with difficult urination and dribbling; labor-related strangury occurs after sexual intercourse; cold strangury involves chills before urination; gao-strangury involves discharge resembling paste; stone strangury involves stones formed from condensed essence; hematuria is also known as blood strangury. Fresh red urine indicates excess heat in the Heart and Small Intestine; dark or turbid urine indicates deficiency-cold in the Kidneys and Bladder. Zhang Zihe stated: Stone strangury is caused by heat transferring from the Liver meridian to the uterus, which over time boils down into stones, not a disease of the Kidneys or Small Intestine. The general treatment principle for strangury should involve regulating qi, clearing the Heart, calming fire, and promoting diuresis. Tonification is not suitable, as it may exacerbate damp-heat. Achyranthes Bidentata Root (Niuxi, 牛膝) is a key herb for treating strangury, especially suitable for blood strangury; Du Niuxi (Cyathulae Radix, 杜牛膝) can also be used. There are cases where insufficient Middle Qi causes difficulty in urination; these should be treated by tonifying Middle Qi, as the classics state "when qi transforms, urination occurs." Avoid using herbs that promote urination for strangury in such cases). Amenorrhea and difficult labor (due to its downward effect, misuse can cause abortion), bi-sore throat and toothache (guiding fire downward), carbuncles and malignant sores, traumatic injuries and fractures (all above are due to its merit of dispersing evil blood), extracting bamboo or wood splinters (mash and apply; even if the wound closes, the splinter will still expel itself). However, since its nature is downward and it lubricates the orifices, it is contraindicated for seminal emission, spermatorrhea, and leg/knee swelling and pain caused by Spleen Qi sinking.
It originates from Xichuan and Huaqing Prefecture; those that are large, long, and plump are of good quality. For downward effects, use raw; for tonifying formulas, soak in wine and steam. It is incompatible with Testudinis Carapax et Plastrum (Guijia, 龟甲). It fears Baiqian (Adenophorae Radix, 白前). Mutton is contraindicated.