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Taste: Bitter, Cold. Toxicity: Non-toxic. Indications: Primarily treats lower jiao blood stasis, amenorrhea caused by cold-heat patterns, breaks masses and accumulations (abdominal lumps), eliminates retained fluids and retained food, purges the stomach and intestines, pushes out the old to bring forth the new, promotes the smooth flow of water and grain, harmonizes the middle jiao to transform food, and pacifies and harmonizes the five zang organs.

(Dahuang [Rhei Radix et Rhizoma], referred to as "Huangliang" in *Shennong Bencao Jing* [The Divine Farmer's Materia Medica], was later called "Jiangjun" [General] by people because of its efficacy in expelling pathogens and quelling chaos. In ancient times, those from Hexi and Longxi were considered superior. Currently, it is produced in Sichuan, Hedong, and various prefectures in Shanxi and Shaanxi, with those from Sichuan featuring brocade-like patterns being the best. The roots are harvested in August; they contain yellow juice and have a moistening nature. After excavation, they are hung on tree branches and dried over a long period.)

Dahuang tastes bitter and has a cold qi, yellow color, and fragrant odor; it is an agent that rectifies the central earth (spleen/stomach). Its nature moves freely without staying fixed, primarily treating lower jiao blood stasis and blood closure. When qi and blood are in harmony, cold-heat symptoms are also resolved. It not only descends blood stasis and closure but also breaks masses and accumulations, eliminating retained fluids and food. Retained fluids and food stagnate and gather; since old filth is not cleared, it is said to purge the stomach and intestines and push out the old to bring forth the new. When the stomach and intestines are harmonized, water and grain flow smoothly; when old filth is removed, food transformation and middle jiao regulation occur, hence it is said to promote the smooth flow of water and grain and harmonize the middle jiao to transform food. *Suwen: Yuji Zhenzang Lun* states: "The five zang organs all receive qi from the Stomach. The Stomach is the root of the five zang organs. If Stomach qi is peaceful, the five zang organs are also peaceful." Thus, it is also said to pacify and harmonize the five zang organs.

I observe: Dahuang suppresses yang and nourishes yin, possessing the merit of pacifying and harmonizing the five zang organs, which is why it is non-toxic and named "Huangliang" in *Shennong Bencao Jing*. However, its purgative action is swift and fierce, descending blood stasis and breaking accumulations, hence the alias "Jiangjun," and it is listed in the Lower Class.

People in the Northwest possess dense earth qi, with yang qi hidden and stored; heavy use of Dahuang can nourish yin without causing excessive depletion. People in the Southeast have floating earth qi, with yang qi leaking outward; slight use of Dahuang will damage the spleen and stomach. This is due to the differences in the earth qi of the five directions. Furthermore, observing people from all four directions, those with robust constitution and accumulated heat remaining in the interior can benefit from Dahuang's ability to nourish yin and push out the old to bring forth the new; it may be used. For those with innate deficiency-cold, even if the syndrome indicates the need for Dahuang, the dosage should be adjusted according to their constitution. This is due to differences in innate constitution. In the Yangming chapter of *Shanghan Lun*, all three Chengqi Decoctions use Dahuang. Dachengqi Tang [Major Order the Qi Decoction] and Tiaoweichengqi Tang [Regulate the Stomach and Order the Qi Decoction] are used together with Mangxiao [Natrii Sulfas] to承接 (receive/mediate) the fire-heat above and regulate the stomach and intestines, causing downward discharge. Xiaochengqi Tang [Minor Order the Qi Decoction] uses only Dahuang, without Mangxiao, to move dryness and constipation in the stomach and intestines. Once dryness and constipation are moved, yin and yang, upper and lower, inside and outside are all harmonized. Today's practitioners do not understand the essence of *Shanghan Lun*; at the onset, they only use dispersing methods and food-resolving agents; next, they use spleen-stomach harmonizing and grinding methods; finally, they resort to Dahuang for purging. They fail to observe the depth of the muscle surface and meridians and do not comprehend the subtleties of ascending, descending, exiting, and entering. Chest discomfort leads them to claim there is food retention; slight pain upon palpation leads them to insist on food retention. Unresolved external heat leads them to absolutely cut off grain intake; intestinal emptiness with no stool leads them to forcibly purge feces. Prescriptions and medications always end with Dahuang. Those with robust constitutions or shallow pathogenic invasion, though harmed by such treatment, will not die immediately; what should heal in one or two days drags on to ten days; what should heal in ten days drags on to over a month. After recovery, the doctor claims credit. If righteous qi is slightly deficient or pathogens are rampant, yet this method is still used, such doctors, knowing only this single approach, rarely avoid causing death. Alas, doctors entrust life and death; how can they be blind and ignorant, yet pride themselves on noticing the tip of an autumn hair? Failing to consider the main principles while merely envying the catch is shameful. Deviating paths and viewing through a tube, yet remaining unshakably convinced, is even more shameful.