Library

Ze Xie (Alisma Rhizome), with a sweet, sour, and slightly salty taste, is cold in nature. It sinks and descends, belonging to Yin with a slight Yang quality, and is non-toxic. It enters the Foot-Taiyang Bladder Meridian and Foot-Shaoyang Gallbladder Meridian, and can also enter the Kidney.

Ze Xie excels at promoting urination and draining dampness, eliminating sweating in the yin region, and facilitating urination with miraculous effect; it is a divine elixir for removing dampness and quenching thirst.

One might ask: Since Ze Xie is a substance that promotes urination and eliminates dampness, logically, as water and dampness leave, body fluids should naturally decrease. Why does it instead quench thirst? One must understand that Ze Xie not only promotes urination and eliminates dampness but is originally good at nourishing Yin. If there is damp-heat qi in the Kidney, it arises because ingested food and water fail to transform into essence and instead transform into fire. This fire is not the true fire of the Mingmen (Gate of Vitality, the source of original Qi), but rather the evil fire of damp-heat. If this evil fire is not removed, the true fire cannot arise; if the true fire does not arise, the true Water (Yin) cannot be generated. Ze Xie is adept at draining the evil fire from the Kidney; draining the evil fire is precisely how one tonifies the true Water. If it were not for tonifying the fire within the Kidney, why would Master Zhang Zhongjing use Ze Xie in Liuwei Dihuang Wan (Six-Ingredient Pill with Rehmannia)? The Kidney has only tonification methods, no purgation methods; Ze Xie tonifies the Kidney, it does not purge the Kidney, which is absolutely correct. Otherwise, why would purging water result in no thirst? Is this not because it purges evil water? This is clear evidence of generating true Water. Thus, Wuling San (Five-Ingredient Powder with Poria) facilitates the Bladder, and body fluids become naturally moistened.

Someone might say: Ze Xie is purging while simultaneously tonifying; I respectfully accept this teaching. However, what is purged is water, not fire. Your assertion that it purges fire seems unusual. In fact, purging fire without merely purging water has its rationale. The Bladder is the Fu organ of Taiyang; originally, it belongs to Fire, not Water. The inability of water in the Bladder to flow downward is rarely due to Cold but mostly due to Heat. Essentially, if the Bladder lacks Fire, water becomes obstructed; if it has Fire (evil fire), water also becomes obstructed. When Ze Xie is used in Wuling San, although it appears to drain water, it actually drains fire. Because it possesses the property of draining fire, its use yields remarkable results. Otherwise, Lingzhi (Poria) and Baizhu (Atractylodes Macrocephala Rhizome) are sufficient for draining water; why rely heavily on Ze Xie? This principle of draining fire is sound, yet people have not pondered it.

One might ask: Ze Xie has more purgative than tonifying effects, yet you insist it has tonifying properties. I assume this is because Zhang Zhongjing used it in Liuwei Dihuang Wan, hence stating that Ze Xie tonifies while purging. But this applies not only to Liuwei Dihuang Wan. Why not in Wuling San? In all cases of difficult urination, there is no instance of no thirst. Once urination is facilitated, thirst resolves. Wuling San facilitates urination. The resolution of thirst after facilitating urition indicates the generation of body fluids in the mouth. Wuling San drains water from urination; if water leaves and nothing remains to moisten the mouth, thirst should ensue. Yet, there is no thirst, and body fluids are generated. Is this not clear evidence of tonification within purgation? Moreover, the reason for difficult urination is the presence of evil fire in the Bladder. Fire in the Bladder scorches and dries body fluids, causing thirst. In Wuling San, Ze Xie drives out evil fire and preserves true Water. With fire gone, Water rises naturally; with Water rising, body fluids become moistened. These fluids then irrigate the Palace of the Kidney. Who says Ze Xie only purges and does not tonify?

One might ask: Ze Xie is used in Liuwei Dihuang Wan for purging with tonification. What is the intention when used in Shenzi Wan (Eight-Ingredient Pill with Rehmannia, also known as Jin Gui Shen Qi Wan)? The answer is: There is profound meaning. When there is no Fire in the Kidney, Shenzi Wan is used to tonify Fire within Water. However, Fire tends to flare upward. Without medicine to guide it downward, the Dragon-Lei Fire (Ministerial Fire) may well surge upwards with the heat. If using descending medicines that only purge and do not tonify, one fears that during Fire tonification, the Fire will still leak downwards with the Water, rendering the effort futile. If descending medicines only tonify and do not purge, one fears that during Fire tonification, the Fire will not descend with the Water, leading to excessive Fire tonification and potentially causing persistent erection (strong yang不倒). The brilliance lies in Ze Xie’s nature: it promotes urination, and within its purgative action, it contains tonification. It guides Fire downward, reduces excess Fire, and does not damage deficient Fire. It assists Rougui (Cinnamon Bark) and Fuzi (Prepared Aconite Root) to achieve the state of Mutual Interaction between Heart and Kidney (Water-Fire Ji Ji). Who says Zhang Zhongjing’s use of Ze Xie in Shenzi Wan lacks profound significance?

One might ask: The world generally considers Ze Xie a purgative, yet you alone claim it tonifies while purging, and each expounds different views. Besides Shenzi Wan, Liuwei Dihuang Wan, and Wuling San, are there other explanations to broaden my understanding? The essence of Ze Xie can be understood through these three formulas, but they do not fully reveal its wonders. Ze Xie not only drains excess Fire but also drains excess Water; it not only preserves deficient Fire but also preserves deficient Water. This concept of tonification within purgation was fully explained earlier. However, its functions extend beyond this. Ze Xie can enter Water to tonify deficient Fire; it can enter Fire to drain excess Water. For individuals with deficiency-cold who suffer from frequent nocturnal enuresis, this indicates deficient Fire. One would inevitably use herbs like Yizhiren (Biotae Semen), Shanzhuyu (Corni Fructus), and Wuweizi (Schisandrae Fructus) to astringe and stop enuresis. However, using only sour-astringent substances without adding salty-sweet items will lead to increased retention and continued leakage. Ze Xie is salty and sweet. When added to Yizhiren, Shanzhuyu, and Wuweizi, enuresis is instantly cured. If it did not tonify Fire within its purgative action, would it not exacerbate enuresis? For individuals with deficiency-heat who suffer from severe thirst, this indicates deficient Water. One would inevitably use herbs like Xuanshen (Scrophulariae Radix), Shengdihuang (Rehmanniae Radix), Shashen (Glehniae Radix), Digupi (Lycii Cortex), and Ganju (Chrysanthemi Flos) to drain Fire and moisten to relieve thirst. However, using only bitter-cold substances without adding sweet-salty items will lead to increased dryness despite attempts to stop thirst. Ze Xie is sweet and salty. When added to Xuanshen, Shengdihuang, Shashen, Digupi, and Juhua, thirst heals itself. If it did not tonify Water within its purgative action, would it not increase thirst? Thus, the subtle meaning of Ze Xie is as follows.

One might suspect that Ze Xie has both merits and faults, but discussing only its merits without mentioning its faults is not a balanced argument. In reality, when Ze Xie is used alone for promoting urination, it has both merits and faults; when used in combination, it has few faults and many merits. Used alone, it can treat those with excess Water but should not be used for those with deficient Water. Draining excess Water is meritorious; draining deficient Water is faulty. When combined, it is suitable for tonic prescriptions, not for attack/excess-clearing prescriptions. Tonifying deficiency yields many merits; attacking excess yields few faults. Having faults and merits is due to improper human usage, not a fault of Ze Xie itself.

One might ask: Bian Que stated that taking large amounts of Ze Xie causes patients to take too much diuretic effect, implying it is not a Yin-tonifying drug? This is not Bian Que’s words, but rather recorded and transmitted by later generations. When Ze Xie is used in Liuwei Dihuang Wan, Shenzi Wan, and other Kidney-tonifying formulas, where it tonifies without purging, long-term and heavy use brings great benefit and certainly does not harm the eyes. Only in cases of exhausted Kidney Qi, Yang decline with seminal emission, insecure Kidney Qi, seminal slipperiness, and eye pain, should Ze Xie not be taken alone, as this would further deplete deficiency. However, if included among a group of Kidney-tonifying herbs, it is perfectly harmless.