Heart Racing, Loose Stools and Scanty Urine After a Fever? Doctor Zhang Xichun’s Shaoyao Gancang Tang to Replenish Yin Fluids
Search keywords: heart racing / palpitations after a fever / diarrhea after a fever / scanty urine / running to the toilet often
Opening: the moment he mentions peony, half the audience leaves
For the past several talks, Doctor Luo Dalun had been introducing herbs that Doctor Zhang Xichun used again and again — and every one of them was a food as well as a medicine. The audience loved it. But today’s herb is different: bai shao (white peony root) — a genuine, serious medicinal herb.
💬 Note from Doctor Luo: I look at the stats on my WeChat channel, and whenever I talk about herbs that are also foods, tens of thousands of people tune in every day. The moment I mention bai shao, half the audience is gone. But even so, I have to talk about it — because Doctor Zhang Xichun built his formulas around herbs like this. If you don’t understand bai shao, a great many of his later formulas will remain a blur to you. And bai shao is extremely important: the famous blood-nourishing formula Si Wu Tang (Four Substances Decoction) contains bai shao.
The patient: a fifteen- or sixteen-year-old boy who caught a heat illness in spring
Today’s case is about treating an external-contraction illness — and it is quite distinctive. There was a boy of fifteen or sixteen who fell ill in spring. What illness? A warm-pathogen illness (wen bing).
💬 Note from Doctor Luo: What is a warm-pathogen illness? It is an external-contraction illness of a hot nature. When it strikes, you get a sore throat, fever, and other heat signs. Doctor Zhang Xichun mentions warm-pathogen illness several times in his book; today’s case is exactly the aftermath of one.
How sick was he: the high fever broke, and he felt even worse
After treatment, in eight or nine days the great heat had broken — the high fever was gone. But the boy still felt a bit of heat in his chest, and he had xin ji zheng chong (palpitations): his heart raced and pounded, as if he could barely hold himself together.
And more: xiao bian bu li — he urinated very little; da bian hua xie — he was always running to the toilet, with frequent, loose, unformed stools. The pulse? Xu shu — deficient and rapid: the pulse was weak and insufficient, yet beating fast.
💬 Note from Doctor Luo: Friends, notice this combination: the fever is gone, yet he has heart palpitations, scanty urine, loose stools, and a rapid, deficient pulse. What does it tell us? The external pathogen has not been completely cleared — there is still a little heat inside — and, crucially, the body’s water metabolism has gone wrong: water that should leave through the urine is now leaving through the bowels instead.
How Doctor Zhang thought about it: the water went down the wrong road, and the root lay in the body’s fluids
Doctor Zhang Xichun’s diagnosis: the external pathogen was not fully cleared — there was still some heat. So how to drive out that heat? He seized on the key clues: scanty urination and loose stools. Water should normally leave through the urine, and the stools should be normal. Here, the urine was scanty and the bowels were running loose — the whole water metabolism was in disorder.
💬 Note from Doctor Luo: This is a high moment of pattern discrimination. Doctor Zhang did not fixate on the “heat” and hammer it with heat-clearing herbs. Instead, he saw the pivot — the water metabolism. Restore order to the waterways, and the heat naturally has a way out.
The prescription: just two herbs, one sour and one sweet
The formula Doctor Zhang used is wonderfully simple — it is called Shaoyao Gancao Tang (Peony and Licorice Decoction) — only two herbs:
- Raw white peony (sheng bai shao) 2 liang (about 60 g)
- Honey-fried licorice (zhi gancao) 1.5 liang (about 45 g)
Decoct into one large bowl and have the boy drink it slowly, sip by sip.
💬 Note from Doctor Luo: Those two words — “drink it slowly” — are themselves a principle of method. A person depleted of fluids must not be drenched with a big gulp; the medicine should be taken a little at a time so it is absorbed gently. Only then can the yin fluids actually be replenished.
The result: one bowl of medicine, and the illness was cured
And the outcome? After finishing this dose, the illness was cured with a single dose — just these two herbs, one bowl, and the boy recovered.
💬 Note from Doctor Luo: This case rewards close reflection. Doctor Zhang himself pointed out: the Shen Nong Ben Cao Jing (Divine Farmer’s Classic of Materia Medica) says peony boosts qi — it can tonify qi; and Zhang Yuansu — the teacher of Li Dongyuan, known as Jigu Laoren (Old Man of Clean Valley) — said that peony stops diarrhea. Look at this case: the peony stopped the loose stools, and at the same time promoted urination, guiding the heat out through the urine — exactly as Zhang Yuansu said. This is a famous doctor’s precise command of medicinal properties.
Doctor Zhang’s self-criticism: two more herbs should really have been added
Doctor Zhang later added: this formula really should also have included huai shan yao (Chinese yam) and hua shi (talc). But at the time he had not yet mastered that combination thoroughly, so he left them out — and the Shaoyao Gancao Tang alone still worked.
💬 Note from Doctor Luo: You see, Doctor Zhang never hid anything — he even wrote his own “immaturity” at the time into his book. Why add huai shan yao? To tonify the spleen and firm the stools. Why add hua shi? To promote urination and clear heat. This is the more complete usage he later worked out.
What this formula actually treats: cramps, teeth grinding, restless legs
So what is Shaoyao Gancao Tang for? It comes from the Shang Han Lun (Treatise on Cold Damage), where Zhang Zhongjing used these two herbs to treat the various spasms and cramps that arise when the body’s fluids are insufficient — when yin and blood are deficient, and the channels and sinews lose their nourishment.
💬 Note from Doctor Luo: This formula is wonderfully useful. Take someone who gets leg cramps at night, someone who grinds their teeth at night, or someone with restless legs syndrome — the legs constantly twitch, uncontrollably. Shaoyao Gancao Tang generally works in a single dose: bai shao 30 g with honey-fried licorice 15 g — the same ratio as Zhang Zhongjing’s original formula — and the legs stop twitching, the teeth grinding stops. Why does it stop teeth grinding? For the same reason: the sinews are undernourished. When the fluids inside are insufficient and the channels have no moisture to nourish them, you get spasms, cramps, and pain.
The finishing touch: sour-sweet yin generation — once the fluids are sufficient, a hundred complaints vanish
Why is it so effective? Because these spasms are all caused by insufficient fluids — there is not enough liquid to nourish the channels. And bai shao tastes sour, licorice tastes sweet; when sour and sweet are combined, they generate yin fluids — Chinese medicine calls this suan gan hua yin (sour-sweet yin generation).
💬 Note from Doctor Luo: Some friends have read my earlier articles: wumei (smoked plum) boiled with white sugar is also sour-sweet yin generation. Chinese medicine holds that sour and sweet together generate yin fluids and replenish the yin within the body; once the yin is sufficient, the channels are nourished, and cramps and spasms resolve on their own.
A bonus: why can Shaoyao Gancao Tang treat an external-contraction illness?
So why can it treat an external-contraction illness? The reasoning is this: many external-contraction and warm-pathogen illnesses occur because the body’s fluids are insufficient, so qi and blood cannot circulate properly, and only then does the external pathogen sneak in to cause trouble. Replenish the yin fluids, and the body starts to run on its own again — the body itself can expel the external pathogen.
💬 Note from Doctor Luo: That is the mechanism by which Shaoyao Gancao Tang treats the late stage of a warm-pathogen illness: sour-sweet yin generation, replenishing the fluids, restoring normal qi-blood circulation — and the external pathogen can no longer stay. Add Doctor Zhang’s masterly use of bai shao to stop diarrhea and promote urination, and the fluid metabolism returns to normal — several effects working together, and a single bowl of medicine wiped out every symptom of the late-stage warm-pathogen illness. That is Doctor Zhang Xichun: his command of formulas was so precise that he stands among the great masters of Chinese medicine.
What we learned today
So what do we all take away today? Bai shao (white peony) and licorice combined can generate yin from sour and sweet flavors and replenish the body’s fluids. Once the fluids are sufficient, channel spasms, cramps, and restless legs syndrome all resolve.
💬 Note from Doctor Luo: Once you understand sour-sweet yin generation, you have truly entered the door of understanding bai shao. And Doctor Zhang Xichun’s stories of building formulas around bai shao are far from over.
Compiled from Doctor Luo Dalun’s explanations of Doctor Zhang Xichun’s case records; the case is from Records of Chinese Medicine with Western Reference (《医学衷中参西录》, published in installments 1918–1934).