Yuzhu San: A TCM Formula for Nourishing Blood and Moisting the Intestines

Yuzhu San appears repeatedly in ancient TCM texts (e.g., Medical Formulas Examined, Confucians’ Duties in Serving Parents, Systematic Reflection on External Medicine). It is a classic famous formula that nourishes blood, moistens the intestines, unblocks the bowels, and drains fire. It consists of equal amounts of Chuanxiong (Ligusticum), Danggui (Angelica), Shaoyao (Paeonia), Dihuang (Rehmannia), Mangxiao (mirabilite), Dahuang (Rheum), and Zhi Gancao (honey-fried Licorice), decocted in water and taken before meals.

This formula treats patients with sores and ulcers who have heat binding the stomach and intestines with depletion of yin and blood, presenting as swollen, painful, feverish lesions; dry mouth and tongue; chest and abdominal fullness; dry stools; and fatigue and lack of strength.

This formula is a combination of two classic TCM formulas: the blood-regulating Siwu Decoction (Chuanxiong, Danggui, Shaoyao, Dihuang) and Tiaowei Chengqi Decoction.

Siwu Decoction treats blood deficiency, blood heat, and blood stasis. For blood deficiency, use Shudihuang (processed Rehmannia) and Baishao (white Paeonia); for blood heat and stasis, use Shengdihuang (raw Rehmannia) and Chishao (red Paeonia); for severe constipation, regardless of deficiency or stasis, use Shengdihuang, because raw Rehmannia also moistens the intestines and unblocks the bowels.

Tiaowei Chengqi Decoction comes from the Shanghan Lun and is the representative formula for Yangming disease with dryness-heat in the stomach and intestines, presenting as constipation, intestinal obstruction, dry mouth and tongue, steaming fever, abdominal fullness, irritability and delirious speech, yellow greasy tongue coating, slippery rapid pulse, skin eruptions, vomiting and epistaxis, oral ulcers, and sore swollen throat. Of the three Chengqi Decoctions in the Shanghan Lun (Da Chengqi, Xiao Chengqi, Tiaowei Chengqi), Tiaowei Chengqi has the mildest purgative action and mainly drains heat. Patients with Tiaowei Chengqi pattern have abdominal fullness that should be less severe than in Da Chengqi patterns.

Combining Siwu Decoction and Tiaowei Chengqi Decoction yields a formula that both supports zheng qi (vital qi) and dispels pathogen, treating both root and manifestation. It suits patients with fractures, cerebrovascular accidents, late-stage infection, and late-stage cancer who have swollen painful feverish lesions along with dry mouth and constipation. The original dose was five fen of each herb, roughly 2–3 g each by modern measure; that is, 2–3 g per herb, decocted and taken before meals.

Here Dahuang should be added later: after the other herbs are done decocting, add Dahuang and boil only another 3–5 minutes; prolonged boiling destroys its active components. Mangxiao is not decocted; after the other herbs are done, put the Mirabilite directly into the strained liquid to dissolve. The above dose is for one serving, not a whole day.

After taking one dose, observe for eight hours to see whether the bowels have moved. If they have, the next time Dahuang, Mangxiao, and Zhi Gancao should be omitted, because over-purgation easily causes diarrhea. If after eight hours the patient still cannot pass stool, the dose may be increased—each increase may double the amount; after taking, observe about eight hours; if the bowels still do not move, continue increasing.

When I treated a patient with intractable constipation, I gradually increased Dahuang and Mangxiao up to 30 g; below 30 g the patient could not defecate, and at 30 g there were no adverse reactions. But for most patients, Dahuang above 10 g risks diarrhea, so doses should be increased gradually to ensure safety.