Da Ban Xia Tang (Major Pinellia Decoction) dà bàn xià tāng · 大半夏汤

Safety. Three ingredients: 半夏 (pinellia rhizome), 人参 (ginseng root), and 白蜜 (white honey). Quantities, preparation and method of taking are deliberately not listed here. The line it answers is short — 胃反呕吐者，大半夏汤主之 — for the one who vomits in 胃反, this formula governs. 胃反 is not a synonym for nausea. In the classical descriptions it means food brought up long after it was eaten: eaten in the morning, returned at evening; eaten at evening, returned in the morning. The interval is the point. What is being drawn is not an irritated stomach but a stomach that has not emptied. That interval has a modern name, and this library will use it, because the reader who meets the English phrase first deserves to find it here: delayed gastric emptying. Today it is worked up as gastric outlet obstruction, gastroparesis, bezoar, postoperative gastric stasis, and drug-induced delay. One branch matters more than the rest — in an adult, vomiting food eaten many hours earlier, with weight loss, can be obstruction, and obstruction is a structural problem that no decoction resolves. This library does not offer any management plan for it. It says only that this is the picture the classical line draws, and that the picture belongs on a clinician’s desk rather than in a self-care decision. Two of the three ingredients carry their own notes. 半夏 raw is a mucosal hazard: the needle-shaped calcium oxalate crystals and the lectin in the unprepared rhizome can swell the tongue and throat and threaten the airway; only the prepared form belongs in a formula, which is why this entry names it as processed. 人参 — Panax ginseng — has published case reports of interaction with warfarin and is discussed in relation to hormone-sensitive conditions. "Case reports exist" is the honest strength of that evidence, and this library does not inflate it. The third is the one that surprises people: 白蜜, honey, in a quantity the classical texts treat as substantial rather than as a sweetener. Honey is a sugar load. It is also the one known dietary source of infant botulism, which is why no honey, raw or processed, is given to infants under twelve months in every jurisdiction that has issued guidance on the matter. An ordinary food is not the same thing as an inert food — a point this library has now made with 粳米, with 羊肉 in the previous batch, and here with honey. Chinese-language clinical literature on 大半夏汤 exists, in postoperative gastric stasis and in nausea pictures among others; the studies are small and their methods limited. This library records that the literature exists. It does not record that efficacy has been established.