据《本经》主伤中、五劳、六极、羸瘦、崩中、绝脉、补虚、益气云云，则桑白皮补肺
也。
《别录》则主肺中水气、唾血、热渴、水肿、腹满，胪胀、利水道、去寸白、缝金疮，似桑
白皮又泻肺也。岂相背哉？盖《本经》“中”字皆指胃言，胃主肌肉，百脉秉谷气而成，则
羸瘦、绝脉，亦系胃病。补虚者补胃之虚，益气者益胃之气。胃以下行为顺，上逆则肺不平
，而肺病作。《本经》着治胃之效，而肺之平，不言可喻也。《别录》以经义隐约，故推衍
之，其主治皆胃逆陵肺之症，一本一标，词相反，义相成。《肘后方》以之治消渴尿多及产
后下血，是宗《本经》为用。钱仲阳泻白散治小儿肺经实热，是宗《别录》为用。
仲景以百合治百合病专方也，诸家注从未有能道其故者。案《本草经》百合除邪气，利
大小
便。百合病症状虽变幻不一，要之，小便赤黄一症则有定。仲景于至无定中求其有定者，以
立延医之准，此百合病所以必用百合也。百合病重在小便，故于头痛、头淅淅、头眩诸足以
卜愈期者，皆于小便时诊之。凡辨疑难症，皆当准此。夫古人至奇之法，实有至常之理。浅
人泥于百合补肺之说，因以肺朝百脉为之解，浅也。又百合病者，由于余邪逗留，血气不润
所致。如意欲食而或美及欲卧欲行云云，状其无大邪之抑，正气有时得伸也；复不能食至不
用闻臭、不能卧、不能行云云，状其气血少润也。如寒如热，肌中不润而滞涩也；无寒无热
，余邪不能作势也；口苦，胃液被余邪所吸，不能消净食物也；得药剧吐利，胃液不充，反
为药所胜也；脉微数，微为血气少，数为邪气止也；溺时痛见于头者，溺为去液之事，故病
液少者，卜之于此，下虚则上实也。此证之于症而合者也。其治法，专以滋润为主，故本方
于百合外，加生地汁，津血并润也。汗下吐皆伤液，故随上下之所伤而救之。知母、鸡黄皆
滋润之品。滑石为润下之品。惟赭能逐邪，欲乘其方下而逐之也。变渴，则栝蒌、牡蛎；变
发热，则滑石。无非取乎其润。此证之于方而合者也。然后知《本经》百合除邪气、利大小
便云云，皆润之之效也。大抵病至邪留正虚之时，攻则害正，补则碍邪，惟有润之，使正纾
邪浮，始可设法逐邪。其逐邪之法，总不出伤寒差已后更发热者，小柴胡汤主之，脉浮者以
汗
解之，脉沉实者以下解之数语，决不以百合数方了事也。惟至此时，则病之局势已移，不得
仍以百合称，故百合病止此耳！读仲景书，如读《春秋左传》，当取他传，续此传后，而后
纪事之本末始全。
根据《神农本草经》记载，桑白皮主治伤中、五劳、六极、羸瘦、崩中、绝脉、补虚、益气等症，这说明桑白皮具有补肺的作用。
《名医别录》则记载其主治肺中水气、唾血、热渴、水肿、腹满、胪胀（腹部皮肤肿胀）、利水道、去寸白（肠道寄生虫）、缝金疮，这似乎表明桑白皮又具有泻肺的作用。这两者难道相互矛盾吗？其实，《本经》中的“中”字都是指胃而言。胃主肌肉，全身经脉都依赖水谷之气而形成，所以羸瘦、绝脉，也属于胃病范畴。所谓补虚，是补胃之虚；所谓益气，是益胃之气。胃的气机以下行为顺，如果上逆，就会导致肺气不平和，从而引发肺病。《本经》着重记载了治疗胃病的功效，而肺气平和的道理就不言自明了。《别录》因为经文含义隐晦，所以进行了推演发挥，其主治症状都是胃气上逆凌犯肺脏的表现，这是一本一标的关系，文字看似相反，但义理相辅相成。《肘后备急方》用桑白皮治疗消渴尿多及产后下血，这是遵循《本经》的用法。钱乙（钱仲阳）的泻白散治疗小儿肺经实热，这是遵循《别录》的用法。
张仲景用百合作为治疗百合病的专用方剂，各家注解从未有人能阐明其中的缘故。查考《神农本草经》，百合能除邪气，利大小便。百合病的症状虽然变幻不一，但小便赤黄这一症状则是确定的。张仲景在变化无常的症状中寻找确定的指标，以此作为确立诊疗标准的依据，这就是百合病必须使用百合的原因。百合病的关键在于小便，所以在头痛、头冷颤、头晕等足以推断预后时期的症状中，都是在患者排尿时进行诊察。凡是辨别疑难病症，都应当以此为准则。古人的奇特疗法，实际上蕴含着平常的道理。浅薄之人拘泥于百合补肺的说法，因此用“肺朝百脉”来解释，这是很肤浅的。另外，百合病是由于余热邪气逗留体内，导致气血不能滋润所致。像想吃东西有时觉得美味，想睡觉想行走等，描述的是没有大邪气压抑，正气有时得以舒展的状态；又像不能吃直到听不到气味、不能睡、不能走等，描述的是气血缺乏滋润的状态。像怕冷又像发热，是因为肌肤内部不滋润而滞涩；没有寒也没有热，是因为余邪不能形成势态；口苦，是因为胃液被余邪吸收，不能消化干净食物；服药后剧烈呕吐腹泻，是因为胃液不充盈，反而被药力所胜；脉象微数，微表示气血少，数表示邪气停止；排尿时疼痛反映在头部，是因为排尿是流失津液的过程，所以病液少的人，可以从这里推断，下虚则上实。这个证候与症状是吻合的。其治疗方法，专门以滋润为主，所以原方在百合之外，加入生地黄汁，使津液和血液同时得到滋润。发汗、攻下、催吐都会损伤津液，所以要随着上下部位受损的情况进行救治。知母、鸡子黄（鸡蛋黄）都是滋润的药物。滑石是润下的药物。只有代赭石能驱逐邪气，想要趁着药力下行时驱逐它。如果出现口渴，就用瓜蒌、牡蛎；出现发热，就用滑石。无非是取其滋润的作用。这个证候与方药也是吻合的。由此可知，《本经》记载百合除邪气、利大小便等，都是滋润的功效。大抵疾病到了邪气留存、正气虚弱的时候，攻伐会伤害正气，滋补会阻碍邪气排出，只有滋润，使正气舒缓、邪气浮露，才可以设法驱逐邪气。其驱逐邪气的方法，总离不开伤寒病愈后再次发热者，用小柴胡汤主治，脉浮的用汗法解表，脉沉实的用下法通里这几句话，绝不会仅仅用几个百合方剂就了事。只是到了这个时候，病势格局已经改变，不能再仍然称为百合病，所以百合病的治疗到此为止！阅读张仲景的书，就像阅读《春秋左传》，应当参考其他传记，续接在这篇传记之后，然后纪事的始末才完整。
According to the *Shennong Bencao Jing* (Divine Farmer's Materia Medica), Sangbaipi (Cortex Mori Radicis) is indicated for injury to the middle jiao, five types of exhaustion, six extremes, emaciation, metrorrhagia, interrupted pulse, tonifying deficiency, and benefiting qi. This indicates that Sangbaipi tonifies the Lung.
The *Mingyi Bielu* (Additional Records of Famous Physicians) states that it treats water-qiang in the Lung, hemoptysis, thirst due to heat, edema, abdominal fullness, distension of the skin (luzhang), promoting urination, expelling tapeworms (cunbai), and suturing metal wounds. This seems to suggest that Sangbaipi also drains the Lung. Are these contradictory? Actually, the character "zhong" (middle) in the *Bencao Jing* refers to the Stomach. The Stomach governs the muscles, and all meridians derive their qi from grain and water. Therefore, emaciation and interrupted pulse are also related to Stomach disease. Tonifying deficiency means tonifying Stomach deficiency; benefiting qi means benefiting Stomach qi. The Stomach's qi moves downward smoothly; if it rebels upward, the Lung's qi becomes unharmonious, leading to Lung disease. The *Bencao Jing* emphasizes the efficacy of treating the Stomach, implying that the harmony of the Lung is self-evident. The *Bielu*, finding the original text obscure, elaborated upon it. Its indications are all symptoms of Stomach qi rebelling and encroaching upon the Lung. They share the same root but differ in manifestation; the words appear opposite, but the principles complement each other. The *Zhouhou Beiji Fang* (Handbook of Prescriptions for Emergencies) uses it to treat diabetes with polyuria and postpartum bleeding, following the usage of the *Bencao Jing*. Qian Zhongyang’s Xiebai San (White-Draining Powder) treats excess heat in the Lung meridian in children, following the usage of the *Bielu*.
Zhang Zhongjing used Baihe (Lily Bulb) as the specific formula for Baihe Bing (Lily Disease). None of the commentators have been able to explain the reason. According to the *Bencao Jing*, Baihe eliminates pathogenic factors and promotes urination and defecation. Although the symptoms of Baihe Bing vary, the symptom of dark yellow urine is consistent. Zhang Zhongjing sought the constant amidst the variable to establish a standard for diagnosis, which is why Baihe must be used for Baihe Bing. Baihe Bing focuses on urination; therefore, for symptoms such as headache, chills, and dizziness that help predict the prognosis, diagnosis is made during urination. When differentiating difficult cases, one should follow this principle. Ancient strange methods actually contain ordinary principles. Superficial people stick to the idea that Baihe tonifies the Lung and interpret it via "the Lung directs all meridians," which is shallow. Furthermore, Baihe Bing is caused by lingering residual pathogens leading to a lack of moistening in blood and qi. Symptoms like desiring food or finding it delicious, wanting to lie down or walk, describe a state where major pathogens do not suppress, and healthy qi occasionally extends itself. Symptoms like inability to eat, aversion to smells, inability to lie down or walk, describe a state where blood and qi lack moistening. Feeling cold yet hot indicates stagnation and friction due to lack of moistening in the muscles. No cold or heat indicates that residual pathogens cannot gain momentum. Bitter taste in the mouth occurs because stomach fluids are absorbed by residual pathogens and cannot digest food completely. Severe vomiting and diarrhea after taking medicine occur because stomach fluids are insufficient and are overwhelmed by the medicinal force. A faint and rapid pulse indicates faintness due to low blood and qi, and rapidity due to the cessation of pathogenic activity. Pain in the head during urination occurs because urination involves fluid loss; thus, for diseases with low body fluids, prognosis is derived here: lower deficiency leads to upper excess. This syndrome matches the symptoms. The treatment method focuses primarily on moistening. Therefore, besides Baihe, Shengdizhi (Fresh Rehmanniae Radix Juice) is added to moisten both fluids and blood. Sweating, purging, and vomiting all damage fluids, so rescue measures are taken according to the site of injury. Zimu (Anemarrhenae Rhizoma) and Jihuang (Galli Yolkum) are moistening agents. Huashi (Talcum) is a descending moistening agent. Only Zhe (Hematitum) can drive out pathogens, aiming to expel them while the medicine descends. If thirst changes, Gualou (Trichosanthis Fructus) and Muli (Concha Ostreae) are used; if fever changes, Huashi is used. All aim at moistening. This syndrome matches the formula. Thus, we understand that the *Bencao Jing*'s statement that Baihe eliminates pathogens and promotes urination/defecation is an effect of moistening. Generally, when a disease reaches a stage of lingering pathogens and deficient healthy qi, attacking harms the healthy qi, and tonifying obstructs the pathogens. Only by moistening can the healthy qi relax and the pathogens float to the surface, allowing for methods to expel pathogens. These methods generally do not go beyond the saying in Shanghan Lun regarding fever after recovery: use Xiaochaihu Tang (Minor Bupleurum Decoction); if the pulse is floating, resolve via sweating; if deep and solid, resolve via purging. It certainly does not end with just a few Baihe formulas. However, at this stage, the disease pattern has shifted, so it can no longer be called Baihe Bing, hence the treatment of Baihe Bing ends here! Reading Zhang Zhongjing’s books is like reading the *Zuo Zhuan*; one must refer to other commentaries and continue after this section to fully understand the chronology.