Xing Su San (Apricot Kernel and Perilla Leaf Powder) xìng sū sǎn · 杏苏散

Safety. This formula belongs to a pair. In the Wenbing Tiaobian the warm-dryness and cool-dryness presentations are handled by two different formulas, Sang Xing Tang and this one, and the distinction between them is a distinction inside a traditional seasonal framework rather than between two modern diagnoses. 'Cool dryness' describes a presentation of cough with a small amount of thin sputum, a dry nose and throat, and chills without much sweating, classically placed in late autumn. A reader should not take that category and use it to sort out their own cough, because cough has a differential that the category does not contain: a cough lasting more than three weeks, coughing blood, unintentional weight loss, night sweats, or a cough in a smoker or ex-smoker all need assessment, and tuberculosis and lung cancer are on that list. - The ingredient that needs the clearest explanation is 杏仁, bitter apricot kernel. It contains amygdalin, a cyanogenic glycoside, which means that when it is chewed, crushed or digested it can release cyanide. Poisoning from apricot kernels is documented in the medical literature, children are at greater risk because a smaller amount does the harm, and the fatal cases involve raw or lightly processed kernels. This is why the material is processed and why it is not a food that can be eaten freely. - 半夏, pinellia, is the second ingredient with a real toxicology. The raw rhizome contains needle-shaped calcium oxalate crystals and a lectin; chewing it causes immediate and severe burning and swelling of the mouth and throat, and swelling in that location can threaten the airway. Only the processed forms belong in any preparation, and the classical incompatibility rule puts pinellia against the aconite group. - 枳壳 comes from bitter orange and contains synephrine-type adrenergic amines, which is a reason for caution in people with hypertension, heart rhythm problems or glaucoma, and for anyone taking stimulant or decongestant-type medicines. - 甘草, licorice, in sustained amounts produces a mineralocorticoid-like syndrome of sodium and water retention, potassium loss and raised blood pressure, and it interacts with digoxin, diuretics and corticosteroids. - 前胡 is an apiaceous root, and as with other members of that family a furanocoumarin photosensitivity is plausible though not well documented for this article. - Whether this formula shortens a cold or changes the course of any respiratory illness has not been established by well-conducted controlled trials; the honest verdict is unproven. - Quantities are for a licensed practitioner to decide, and are deliberately not listed here.