气味苦酸平，无毒。主寒湿痿痹、四肢拘挛、膝痛不可屈伸，逐血气伤热火烂，堕胎
。久服轻身耐老。
（牛膝《本经》名百倍。始出河内川谷及临朐，今江淮闽粤关中皆有，然不及怀庆川中
者佳。春生苗，枝节两两相对，故又名对节草，其根一本直下，长二三尺，以肥阔粗大者为
上。）
《本经》谓∶百倍气味苦酸，概根苗而言也。今时所用，乃根下之茎，味甘臭酸，其性
微寒。《易》曰∶干为马，坤为牛，牛之力在膝，取名牛膝者，禀太阴湿土之气化，而能资
养筋骨也。主治寒湿痿痹，言或因于寒，或因于湿，而成痿痹之证也。痿痹则四肢拘挛，四
肢拘挛，则膝痛不可屈伸。牛膝禀湿土柔和之化，而资养筋骨，故能治之。血气伤热火烂，
言血气为热所伤，则为火烂之证。牛膝味甘性寒，故可逐也。根下之茎，形如大筋，性唯下
泄，故堕胎。久服则筋骨强健，故轻身耐老。
气味辛平，无毒。主腰膝痛，补中，盖精气，坚筋骨，强志，除阴下痒湿，小便余沥
。久服轻身耐老。
（杜仲木皮，状如浓朴，折之有白绵相连，故一名木绵。杜字从土，仲者中也，此木始
出豫州山谷，得中土之精，《本经》所以名杜仲也。李时珍曰∶有杜仲，服此得道，因以名
之谬矣。在唐宋本草或有之矣，《神农本经》未必然也。）
杜仲皮色黑而味辛平，禀阳明、少阴金水之精气。腰膝痛者，腰乃肾府，少阴主之。膝
属大
筋，阳明主之。杜仲禀少阴、阳明之气，故腰膝之痛可治也。补中者，补阳明之中土也。益
精气者，益少阴肾精之气也。坚筋骨者，坚阳明所属之筋，少阴所主之骨也。强志者，所以
补肾也。阳明燥气下行，故除阴下痒湿，小便余沥。久服则金水相生，精气充足，故轻身耐
老。
愚按∶桑皮、桑叶有丝，蚕食桑而结茧，其色洁白，其质坚牢，禀金气也。藕与莲梗有
丝，
[Flavor, Nature, and Actions] Bitter, sour, neutral in nature, non-toxic. Primarily treats flaccidity and bi-syndrome (painful obstruction syndrome) caused by cold-dampness, spasticity of the four limbs, knee pain with inability to flex or extend, expels blood-qi injury leading to heat-fire rotting, and induces abortion. Long-term consumption lightens the body and delays aging.
(Niu Xi [Achyranthis Bidentatae Radix], known as "Bai Bei" in *Shennong Bencao Jing*, originally grew in Chuan Valley of He Nei and Lin Qu. It is now found throughout Jianghuai, Min Yue, and Guanzhong, but those from Huaiqing Prefecture are superior. Sprouts emerge in spring; branches and nodes grow pairwise, hence also called "Dui Jie Cao" (Opposite-Joint Grass). Its root is a single main taproot growing straight down, two to three chi long, with thick, broad, and large roots being of the highest quality.)
*Shennong Bencao Jing* states that Bai Bei has a bitter and sour flavor, referring generally to both root and herb. The part currently used is the stem below the root, which is sweet, fetid, and sour in flavor, with a slightly cold nature. The *I Ching* says: Qian represents the horse, Kun represents the ox. The ox's strength lies in its knees. Named Niu Xi because it inherits the qi transformation of Taiyin Damp-Earth, thereby nourishing sinews and bones. Treating cold-damp flaccidity and bi-syndrome implies that flaccidity and bi-syndrome may arise from cold or dampness. Flaccidity and bi-syndrome lead to spasticity of the four limbs; spasticity of the four limbs leads to knee pain with inability to flex or extend. Niu Xi inherits the gentle transformation of Damp-Earth to nourish sinews and bones, thus treating these conditions. "Blood-qi injury leading to heat-fire rotting" means that when blood-qi is injured by heat, it results in a condition resembling fire-burning rot. Niu Xi is sweet in flavor and cold in nature, thus able to expel this pathogen. The stem below the root resembles large sinews in shape and possesses a descending-draining nature, hence inducing abortion. Long-term consumption strengthens sinews and bones, thus lightening the body and delaying aging.
[Flavor, Nature, and Actions] Pungent, neutral in nature, non-toxic. Primarily treats waist and knee pain, tonifies the Middle Jiao, replenishes essence and qi, consolidates sinews and bones, strengthens willpower, eliminates itching and dampness in the genital region, and stops dribbling urine. Long-term consumption lightens the body and delays aging.
(Du Zhong [Eucommiae Cortex] bark resembles Hou Po [Magnoliae Officinalis Cortex]; when broken, white fibrous strands connect it, hence another name is Mu Mian. "Du" contains the radical for earth; "Zhong" means middle. This tree originally grew in the valleys of Yu Zhou, inheriting the essence of Central Earth, which is why *Shennong Bencao Jing* named it Du Zhong. Li Shizhen stated: "There is Du Zhong; taking this allows one to attain the Dao," attributing the name to this is erroneous. Such claims may exist in Tang-Song materia medica, but likely not in *Shennong Bencao Jing*.)
Du Zhong bark is black in color and pungent-neutral in flavor, inheriting the essence and qi of Yangming and Shaoyin Metal-Water. Waist and knee pain: the waist is the mansion of the Kidney, governed by Shaoyin. The knee belongs to large sinews, governed by Yangming. Du Zhong inherits the qi of Shaoyin and Yangming, thus treating waist and knee pain. Tonifying the Middle refers to tonifying the Central Earth of Yangming. Replenishing essence and qi refers to benefiting the kidney essence and qi of Shaoyin. Consolidating sinews and bones refers to strengthening the sinews belonging to Yangming and the bones governed by Shaoyin. Strengthening willpower serves to tonify the Kidney. Yangming dryness-qi descends, thus eliminating itching and dampness in the genital region and dribbling urine. Long-term consumption generates Metal-Water mutual generation, ensuring sufficient essence and qi, thus lightening the body and delaying aging.
The author notes: Sang Pi [Mori Cortex] and Sang Ye [Mori Folium] contain silk fibers. Silkworms eat mulberry leaves to form cocoons; their color is pure white, and their texture is firm and durable, indicating an inheritance of Metal qi. Lotus root and lotus stems contain silk fibers,