By Eric Brand

In Chinese medicine, a variety of different formulas for supplementing yin provide us with a wide range of clinical choices for our patients. We have Er Zhi Wan (Double Supreme Pill), Liu Wei Di Huang Wan (Six-Ingredient Rehmannia Pill), Zuo Gui Wan (Left-Restoring [Kidney Yin] Pill), and Da Bu Yin Wan (Major Yin Supplementation Pill), just to name a few. How do we choose which one to use for any given patient? What are their special characteristics and optimal conditions for use?

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Patients that suffer from yin vacuity often present with heat symptoms, just as people that suffer from spleen vacuity often present with dampness. In spleen vacuity, we try to assess the degree of qi vacuity and the degree of dampness. In formula terms, this is reflected in a somewhat linear progression from purely supplementing formulas like Si Jun Zi Tang to formulas that treat a combination of qi vacuity and dampness like Liu Jun Zi Tang (mild to moderate dampness) and Xiang Sha Liu Jun Zi Tang (more pronounced symptoms of damp obstruction). In the case of yin vacuity with heat, we use a spectrum of formulas that range from supplementing formulas with little focus on heat (such as Liu Wei Di Huang Wan) to more strongly heat-clearing, yin-nourishing formulas such as Da Bu Yin Wan, Zhi Bai Di Huang Wan, and Dang Gui Liu Huang Tang. So the first question is: does the patient have heat?

If the patient has heat, Zhi Bai Di Huang Wan, Da Bu Yin Wan, and Dang Gui Liu Huang Tang are good places to start. If the patient has strong heat signs and a chief complaint of sweating, consider Dang Gui Liu Huang Tang (click here to read more about this formula). If the patient has more moderate heat signs or a chief compliant unrelated to sweating, Da Bu Yin Wan or Zhi Bai Di Huang Wan may be a better place to start. Dang Gui Liu Huang Tang is more symptomatically oriented, as it specifically focuses on sweating, whereas Da Bu Yin Wan and Zhi Bai Di Huang Wan are more broadly indicated for yin vacuity with heat in general.

What are the differences between these heat-clearing, yin-supplementing formulas? To start, Da Bu Yin Wan is the smallest and least complex. It has only four main ingredients: Shu Di Huang, Gui Ban, Zhi Mu, and Huang Bai. Created by Zhu Dan-Xi, this formula was one of the first formulas to popularize the use of Gui Ban as a yin-supplementing agent. As a “product of flesh and blood” (血肉之品xue rou zhi pin), Gui Ban is thought to be particularly powerful; it subdues yang and fortifies the bones in addition to supplementing yin. Zhi Mu, Huang Bai, and Shu Di Huang are all found in Zhi Bai Di Huang Wan, but Zhi Bai Di Huang Wan additionally contains Mu Dan Pi, Fu Ling, Ze Xie, Shan Yao, and Shan Zhu Yu. These agents allow the formula to achieve its legendary balance between supplementing and draining medicinals, but the addition of more ingredients makes the formula slightly more complicated. If one wants a small, concise base formula to elaborate upon, Da Bu Yin Wan is more a straightforward and simple foundation, and its relatively equal emphasis on yin-supplementing and heat-clearing sometimes comes in handy. If Da Bu Yin Wan is used in prepared form, each dosage unit will contain more of the heat-clearing principle from Huang Bai and Zhi Mu than the same amount of Zhi Bai Di Huang Wan would provide. By contrast, Zhi Bai Di Huang Wan is a better choice for vegetarians (no animal products) and it is better suited for patients that present with a co-existing pattern of spleen vacuity and dampness (due to the inclusion of medicinals such as Fu Ling, Ze Xie, and Shan Yao).

Da Bu Yin Wan particularly focuses on the bones (it strengthens the bones in addition to treating steaming bone). The famous formula Hu Qian Wan is essentially a modification of Da Bu Yin Wan that focuses on enriching yin while strengthening sinew and bone. These two formulas came from the same text by Zhu Dan-Xi, and in many ways Hu Qian Wan can be considered an elaboration of the same basic principles seen in Da Bu Yin Wan. However, Hu Qian Wan is stronger for treating emaciation of the lower legs, gait problems, and weak, aching lower back and knees.

The formulas above all combine heat-clearing with yin-supplementation. But what if the patient doesn’t have heat signs?

Er Zhi Wan is a very basic formula unit that only contains two medicinals: Nu Zhen Zi and Mo Han Lian. Mo Han Lian was often called Han Lian Cao until the later editions of the Chinese Pharmacopoeia came out; its official name was changed to avoid confusion with a rarely used local herb that shares the name Han Lian Cao. Mo Han Lian and Nu Zhen Zi are both picked at the equinoxes, Mo Han Lian in the spring and Nu Zhen Zi in the autumn. These two items form a classic “dui yao” pair for supplementing yin without causing stagnation, and the fact that the two are harvested at the equinoxes inspired the name “Er Zhi” (“Double Supreme” or “Two Ultimate”).

Er Zhi Wan is a perfect formula for supplementing yin gradually in patients that cannot tolerate the rich, sticky, cloying agents that are usually used for yin vacuity. Although it is more moderate and gentle in strength than the rehmannia-based formulas, it tends not to produce stagnation. Er Zhi Wan is particularly good for the eyes and hair, but it should be taken for a prolonged period of time because its therapeutic effect is relatively slow compared to yin-supplementing formulas like Zuo Gui Wan. Er Zhi Wan thus fills a unique niche in our repertoire. Since it only contains two medicinals it is ideal for preparations such as pills (very few tablets are required to replicate the traditional method of use).

In comparison to Er Zhi Wan, Liu Wei Di Huang Wan and Zuo Gui Wan are both more rich, cloying formulas that can be problematic in patients with poor digestion. However, this same richness is also their advantage, and it is this very richness that makes these two formulas the quintessential yin-supplementing heroes that they are. Of the two, Liu Wei Di Huang Wan combines three supplementing medicinals with three “draining” medicinals, whereas Zuo Gui Wan focuses purely on supplementation without the inclusion of damp-disinhibiting medicinals such as Ze Xie and Fu Ling.

The best formula for supplementing yin is the one that you know how to use effectively!