气味辛、平，无毒。主腰膝痛，补中益精气，坚筋骨，强志，除阴下痒湿，小便
余沥。久服轻身耐老。
（参张隐庵）杜仲气味辛平，得金之气味；而其皮黑色而属水，是禀阳明、少阴金水之
精气而为用也。腰为肾府，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；益阴者，益少阴之精气也；坚筋骨者，坚阳明所
属之筋，少阴所主之骨也；强志者，肾藏志，肾气得补而壮，气壮而志自强也。阳明燥气下
行，故除阴下湿痒，小便余沥也。久服则水金相生，精气充足，故轻身耐老也。
气味甘、寒，无毒。主伤中，五劳六极，羸瘦，崩中绝脉，补虚益气。（旧
本列为中品，今从《崇原》。）
叶天士曰∶桑皮气寒，禀水气而入肾；味甘无毒，得土味而入脾。中者，中州脾也。脾
为阴气之原，热则中伤，桑皮甘寒，故主伤中。五劳者，五脏劳伤真气也。六极者，六腑之
气虚极也。脏腑俱虚，所以肌肉削而羸瘦也。其主之者，桑皮甘以固脾气而补不足，寒以清
内热而退火邪，邪气退而脾阴充，脾主肌肉，自然肌肉丰而劳极愈矣。崩中者，血脱也；脉
者，血之府；血脱故脉绝不来也。脾统血而为阴气之原，甘能益脾，所以主崩中绝脉也。火
与元气势不两立，气寒清火，味甘益气，气充火退，虚得补而气受益也。
陈修园曰∶今人以补养之药，误认为清肺利水之品，故用多不效。且谓生用大泻肺气，
宜涂蜜炙之。然此药忌火，不可不知。
张隐庵曰∶桑割而复茂，生长之气最盛，故补续之功如此。
【杜仲】
气味辛、平，无毒。主治腰膝疼痛，补益中气，增益精气，坚固筋骨，强壮意志，消除阴部瘙痒潮湿及小便淋漓不尽。长期服用可使人身体轻健，延缓衰老。
（参引张隐庵的观点）杜仲的气味辛平，禀受了金的特性；而其皮色黑且属水，这是禀受阳明经和少阴经的金水精气而发挥作用的。腰部是肾的府邸，由少阴经主司；膝盖属于大筋，由阳明经主司；杜仲禀受了少阴和阳明的气，所以能治疗腰膝疼痛。所谓“补中”，是补益阳明经的中土之气；所谓“益阴”，是补益少阴经的精气；所谓“坚筋骨”，是坚固阳明经所属的筋和少阴经所主的骨；所谓“强志”，是因为肾藏志，肾气得到补益而壮盛，气壮则意志自然坚强。阳明燥气下行，所以能消除阴部的湿痒和小便淋漓不尽。长期服用则金水相生，精气充足，所以能身体轻健，延缓衰老。
【桑根白皮】
气味甘、寒，无毒。主治内伤，五劳六极，形体消瘦，崩漏及脉绝之证，补虚益气。（旧版本草将其列为中品，现依据《崇原》改为下品。）
叶天士说：桑皮气寒，禀受水气而入肾；味甘无毒，得土味而入脾。所谓的“中”，是指中州的脾脏。脾是阴气的源头，受热则中焦受伤，桑皮甘寒，所以主治中焦受损。所谓的“五劳”，是五脏劳损伤及真气；所谓的“六极”，是六腑之气极度虚弱。脏腑都虚弱，所以肌肉消减而形体消瘦。桑皮之所以能主治这些病症，是因为其味甘能固护脾气以补不足，性寒能清内热以退火邪，邪气消退则脾阴充盈，脾主肌肉，自然肌肉丰满，劳损极致的病证也就痊愈了。所谓的“崩中”，是血脱失血；所谓的“脉绝”，是血的府库枯竭；血脱故脉象断绝不来。脾统摄血液并为阴气的源头，甘味能益脾，所以能主治崩中和脉绝。火与元气势不两立，桑皮气寒能清火，味甘能益气，气充火退，虚证得到补益而元气受益。
陈修园说：现在的人把补养的药物，错误地认为是清肺利水的药品，所以用多了没有效果。并且认为生用会大泻肺气，适宜涂蜜炙后使用。然而此药忌火，这一点不可不知道。
张隐庵说：桑树被割取树皮后又能重新茂盛，生长之气最旺盛，所以它具有接续补续的功效如此显著。
[Dou Zhong / Eucommiae Cortex]
Taste: Acrid, Neutral. Toxicity: Non-toxic. Indications: Primarily treats pain in the lower back and knees; tonifies the Middle Jiao (Central Digestive Function), benefits Essence and Qi (Vital Energy); strengthens sinews and bones; fortifies Willpower (Zhi); eliminates dampness and itching in the genital region, and dribbling of urine. Long-term use makes the body light and resistant to aging.
(Referencing Zhang Yin'an): Dou Zhong has an acrid and neutral taste, inheriting the properties of Metal; its bark is black and belongs to Water. Thus, it acts by inheriting the Essence and Qi of Metal and Water from the Yangming and Shaoyin channels. The lower back is the mansion of the Kidney, governed by Shaoyin; the knee belongs to the large sinews, governed by Yangming. Since Dou Zhong inherits the Qi of Shaoyin and Yangming, it can treat pain in the lower back and knees. "Tonifying the Middle" refers to tonifying the Central Earth of the Yangming channel; "Benefiting Yin" refers to benefiting the Essence and Qi of the Shaoyin channel; "Strengthening Sinews and Bones" refers to strengthening the sinews belonging to Yangming and the bones governed by Shaoyin; "Fortifying Willpower" occurs because the Kidney stores Willpower (Zhi); when Kidney Qi is tonified and becomes robust, strong Qi leads to a strong Will. The dry Qi of Yangming descends, thus eliminating dampness and itching in the genital region and urinary dribbling. Long-term use generates Metal and Water mutually, ensuring sufficient Essence and Qi, hence making the body light and resisting aging.
[Sang Gen Bai Pi / Mori Radicis Cortex]
Taste: Sweet, Cold. Toxicity: Non-toxic. Indications: Primarily treats internal injury, Wu Lao Liu Ji (Five Exhaustions and Six Extremes), emaciation, Bing Zhong (Metrorrhagia/Menorrhagia), and Jue Mai (Absence of Pulse); tonifies deficiency and benefits Qi. (Old editions classified this as a Middle-grade herb; now following *Chong Yuan*.)
Ye Tianshi said: Sang Pi (Morus Bark) has a cold nature, inheriting Water Qi to enter the Kidney; it tastes sweet and non-toxic, obtaining the flavor of Earth to enter the Spleen. "Middle" refers to the Middle Jiao Spleen. The Spleen is the source of Yin Qi; heat injures the Middle, so Sang Pi, being sweet and cold, primarily treats injury to the Middle. "Wu Lao" (Five Exhaustions) refers to the damage of True Qi due to labor of the Five Zang Organs. "Liu Ji" (Six Extremes) refers to the extreme deficiency of Qi in the Six Fu Organs. When both Zang and Fu are deficient, muscles waste away leading to emaciation. Sang Pi treats these conditions because its sweetness consolidates Spleen Qi to supplement insufficiency, and its coldness clears internal heat to retreat Fire Pathogens. As pathogens retreat, Spleen Yin fills; since the Spleen governs muscles, muscles naturally become plump, and the condition of extreme exhaustion heals. "Bing Zhong" refers to Blood depletion; "Jue Mai" refers to the vessel of Blood being exhausted; blood depletion causes the pulse to cease. The Spleen controls Blood and is the source of Yin Qi; sweetness benefits the Spleen, thus treating Bing Zhong and Jue Mai. Fire and Original Qi cannot coexist; Sang Pi's coldness clears Fire, and its sweetness benefits Qi. When Qi is full and Fire retreats, deficiency is supplemented and Original Qi benefits.
Chen Xiuyuan said: Nowadays, people mistakenly regard nourishing herbs as agents for clearing Lung Heat and promoting urination, hence frequent use yields no effect. It is also claimed that raw use greatly drains Lung Qi, and honey-fried preparation is preferred. However, one must know that this herb fears fire.
Zhang Yin'an said: The mulberry tree grows lush again after bark cutting, possessing the most vigorous growth Qi, thus demonstrating such significant功效 (efficacy) in replenishing and continuing vitality.