Ling Gui Zhu Gan Tang (Poria, Cassia Twig, Atractylodes and Liquorice Decoction) líng guì zhú gān tāng · 苓桂术甘汤

Safety. Ling Gui Zhu Gan Tang is four ingredients, and the line it comes from in the Jingui Yaolüe is one of the most quoted methodological statements in the whole tradition: 病痰饮者，当以温药和之 — for phlegm-fluid, harmonise it with warm medicinals. The findings recorded alongside are 心下有痰饮, a sensation of fullness or sloshing below the heart, meaning the epigastrium; 胸胁支满, propping fullness in the chest and flanks; and 目眩, dizziness or visual spinning. Elsewhere the same text adds 短气有微饮，当从小便去之 — slight breathlessness from a small amount of fluid, which should be removed through the urine. Read as a modern sentence, that is: epigastric fullness, chest and flank fullness, dizziness, breathlessness, and a stated intention to move fluid out by way of urination. Every one of those sits on a list that has to be excluded first. Dizziness is triaged into central and peripheral before anything else is done, because posterior circulation stroke and cerebellar haemorrhage present as isolated vertigo — often without the focal signs that textbook descriptions promise. Chest or epigastric fullness with breathlessness is assessed for acute coronary syndrome, heart failure, pulmonary embolism and pericardial effusion before it is assessed for anything else, and in older people and in people with diabetes the ischaemic presentation may be breathlessness and epigastric discomfort with no chest pain at all. And "remove it through the urine" is, today, done with loop diuretics in a person whose renal function, sodium and potassium are being watched — which is precisely the context in which the fourth ingredient matters. That fourth ingredient is liquorice. Glycyrrhizin in sustained intake can produce a mineralocorticoid-like picture: sodium and water retention, potassium loss, raised blood pressure, and in reported cases hypokalaemic paralysis and cardiac arrhythmia. Potassium loss is also the mechanism by which digoxin toxicity becomes far more likely, and a potassium-wasting diuretic combined with a potassium-wasting herbal constituent is not additive in a comfortable way. For a formula recorded for exactly the kind of breathlessness that today turns out to be heart failure, this is the most important thing on the page. Identity matters too. 茯苓 is a fungus, Wolfiporia cocos, and it is not 土茯苓, which is a Smilax root from a completely different family; the two are substituted for one another in the market and they are unrelated organisms. 白术 is not 苍术. 桂枝 is cassia twig, and cassia contains coumarin, for which European food safety authorities have set a tolerable daily intake. Liquorice containing glycyrrhizin is itself a recognised source of interactions with conventional medicine, which is why the point above is about arithmetic rather than about herbs. Nothing here is a claim that this composition does what the classical text says it does. It is recorded because the formula states a method — warm it and move it — that remains the vocabulary Chinese medicine uses for retained fluid, and because the findings it was aimed at are precisely the findings that now get a workup before they get a name.