The Formula-Pattern of Dongdi Sanhuang Tang
Dongdi Sanhuang Tang is recorded in Wenbing Tiaobian (Systematized Identification of Warm Diseases). It is composed of "Maimendong (Ophiopogonis Radix) 8 qian, Huanglian (Coptidis Rhizoma) 1 qian, Weigenzhi (fresh Phragmitis Rhizoma juice) half a wine cup (added), Yuanshen (Scrophulariae Radix) 4 qian, Huangbai (Phellodendri Cortex) 1 qian, Yinhualu (Lonicerae flower distillate) half a wine cup (added), Xi Shengdi (raw Rehmanniae Radix) 4 qian, Huangqin (Scutellariae Radix) 1 qian, Sheng Gancao (raw Glycyrrhizae Radix) 3 qian." The decoction method is: "Boil eight cups of water down to three cups; take in three divided doses, stopping when urination becomes free." Wenbing Tiaobian uses it to treat the pattern of exuberant Yangming heat with severe damage to body fluids, clinically presenting as "high fever that does not recede, hot body without sweating, thirst and craving cold drinks, restless agitation, abdominal distension without pain, unbound stools, difficult urination, a red tongue with yellow, dry, rough, aged coating, and a surging rapid pulse that becomes fine on deep pressure."
Dongdi Sanhuang Tang is a formula that clears heat with coldness and engenders yin through sweetness and bitterness. For ease of understanding and memory, we can break this formula down into a combination and modification of three formulas: Zengye Tang, Huanglian Jiedu Tang, and Yinhua Gancao Tang. Zengye Tang consists of Yuanshen, Maimendong, and Shengdi; Huanglian Jiedu Tang consists of Huanglian, Huangbai, Huangqin, and Zhizi; Yinhua Gancao Tang consists of Jinyinhua and Gancao.
This formula removes Zhizi from Huanglian Jiedu Tang and replaces it with Weigenzhi—that is, fresh Lugen (Phragmitis Rhizoma). Lugen is an essential herb for clearing heat and draining fire, and for generating fluids and stopping thirst; thirst with craving cold drinks is one of this formula's key indications. Although Zhizi also clears heat and drains fire, it lacks Lugen's fluid-engendering, thirst-quenching effect. Therefore replacing Zhizi with Lugen is precisely a flexible adaptation of Huanglian Jiedu Tang following the principle of "for this pattern, use this herb."
Broken down this way, the formula is not hard to remember or understand. Zengye Tang is the representative TCM formula for treating dryness, indicated for the pattern of fluid exhaustion and dryness due to Yangming warm disease; Huanglian Jiedu Tang is a heat-clearing formula that clears heat and resolves toxin, drains fire and eliminates restlessness, indicated for triple-burner fire-toxin pattern; Yinhua Gancao Tang is an external sore-treatment formula, indicated for heat-toxin sores and ulcers.
When the three are combined, their indication is precisely the pattern of severe fluid damage caused by lingering heat-toxin. This most often arises when the Yangming exuberant-heat pattern is untreated and drags on. For Yangming exuberant heat, Baihu Tang should be used; if Baihu Tang is not used in time, causing severe fluid damage with profuse sweating, Baihu Jia Renshen Tang should be used; if the patient's fluid depletion is severe, a pattern appears with both heat-toxin and absence of sweating and scanty urine—fluid exhaustion. At this point Baihu Jia Renshen Tang is inappropriate, because the Baihu series of formulas clinically present the "three bigs": big fever, big thirst, big sweating. Using Baihu Jia Renshen Tang without sweating is a mismatch of drug to pattern.
Therefore Dongdi Sanhuang Tang treats patterns of great heat, great thirst, agitation, difficult urination, red tongue, yellow coating, and rapid pulse. These symptoms are seen in various febrile diseases, and also in transformed patterns arising from excessive sweating in warm-heat disease or excessive diuresis in damp-heat patterns. For example, some patients who take fever-reducing and pain-relieving drugs and sweat excessively easily develop these symptoms; patients with pleural effusion or ascites who take too many diuretics also easily develop this phenomenon—all because overtreatment has exhausted the patient's fluids. When correcting an excess, one must heavily use herbs that nourish yin and engender fluids, but because the patient's heat-toxin has not been completely eliminated, one must also address clearing heat and resolving toxin.
In treating such patients, the priority is nourishing yin and engendering fluids; only secondarily does one clear heat and resolve toxin. In this formula, Zengye Tang is used in a heavy dosage, and the proportion among its herbs is altered, with heavy use of sweet-cold Maimendong to engender yin. Huanglian Jiedu Tang is used in a lighter dosage because Huanglian, Huangbai, and Huangqin, while draining fire and resolving toxin, also have the side effect of drying dampness and damaging fluids, so they may only be used lightly. Heat-toxin damaging fluids easily leads to sores and ulcers; adding Yinhua Gancao Tang addresses the external sores caused by heat-toxin. If sores have formed and are relatively severe, and Yinhua Gancao Tang alone is insufficient, Wuwei Xiaodu Yin may be combined.
In treating this fire-toxin damaging yin pattern, free urination indicates that fluids have recovered; therefore this formula specifically notes to stop when urination becomes free.