Source 出处 · Jingui Yaolüe · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. Baihe Dihuang Tang is built for one classical entity: 百合病, lily disease. Jingui Yaolüe describes it in a paragraph that is worth reading as it stands rather than as a diagnosis. The person wants to eat and cannot eat; is often silent; wants to lie down and cannot rest; wants to walk and cannot walk; sometimes food tastes good and sometimes the smell of it is unbearable; feels cold without being cold and hot without being hot; has a bitter taste in the mouth and dark urine. No medicine has helped, and medicine makes it worse, with vomiting and diarrhoea. The text says it is 如有神灵者 - as if spirits were involved - and then adds the clause that matters most: 身形如和, the body looks well.
That last clause is the one a modern reader most needs. A person who looks well and is not well is, today, exactly the person who is told nothing is wrong. The classical text did not resolve that tension; it recorded it. It also recorded its own failures - 诸药不能治，得药则剧吐利, no medicine had worked and medicine made it worse - which is more candour than most classical passages offer about their own limits.
The indication line adds a condition that readers skip: 百合病不经吐下发汗，病形如初者 - the case in which no sweating, vomiting or purging has been used, and the picture is still the original one. The formula is for the untreated case, not for the aftermath of treatment. That is a selection rule written into the indication.
The honest modern statement is that this description does not map onto one disease. It maps onto a differential that has to be gone through before any label is applied: infection, including post-viral states, HIV, syphilis, encephalitis and the prolonged fatigue that follows mononucleosis; metabolic and endocrine causes, with thyroid disease in both directions, hyponatraemia, hypercalcaemia, hypoglycaemia, uraemia, hepatic encephalopathy and adrenal insufficiency; drugs and substances, including sedatives, anticholinergics, antihistamines, antipsychotics, corticosteroids, antiparkinsonian agents, alcohol and withdrawal, and discontinuation effects; neurological causes such as epilepsy, early dementia, the prodromal phase of Parkinson disease, multiple sclerosis and myasthenia; obstructive sleep apnoea; anaemia; malignancy including paraneoplastic syndromes; and psychiatric presentations - depression, anxiety, somatic symptom disorder and trauma-related conditions. Not one item on that list is excluded by a normal physical examination.
Two further classical notes. The method line says 中病，勿更服: stop once it hits, do not repeat. A stop rule written into the method of a formula is rarer than readers expect, and this library treats it as part of the record rather than as decoration. The same line says 大便当如漆 - the stool should turn black like lacquer. Today black stool is a warning sign for upper gastrointestinal bleeding until it is shown to be something else, and iron, bismuth and some foods produce it too. A change in stool colour during any course of care is a question for a clinician, not an expected effect to wait out.
On the materials. Lily bulbs (Lilium species) are eaten as food in many cuisines, and Lilium species are severely nephrotoxic to cats - cats are not a basis for inferring anything about how a person should use this, but a household with cats should know it. Fresh rehmannia juice and prepared rehmannia (熟地黄) are two different products and are not interchangeable. There are no adequate human safety data for this formula in pregnancy or breastfeeding. Small Chinese clinical reports on 百合地黄汤 exist, mostly for sleep and mood complaints, small in scale and limited in method; this library records that the research exists, not that benefit has been established.
百合地黄汤为百合病而设。《金匮要略》对百合病的那段描写，值得照原样读，而不是当成诊断：意欲食复不能食，常默默，欲卧不能卧，欲行不能行，欲饮食或有美时，或有不用闻食臭时，如寒无寒，如热无热，口苦，小便赤；诸药不能治，得药则剧吐利，如有神灵者，身形如和，其脉微数。
其中最要紧的一句是「身形如和」—— 看着没有病容。今天最容易被这句话伤到的，正是检查做完被告知「没有异常」的那个人。古典文献没有消除这个张力，它只是把它记了下来；它还记下了自己的失败：「诸药不能治，得药则剧吐利」—— 药没治好，吃了反而吐利加重。这份坦白，在古典条文里并不常见。
主治条文另有一个常被跳过的限定：「百合病不经吐、下、发汗，病形如初者」—— 未经汗吐下误治、病形仍如初始的那一类。它是为「未经治疗」而设，不是为「治过之后」而设。这是写进主治里的入选条件。
今天必须说清：这段描写不对应某一个病名，而对应一张走完之前不能下结论的鉴别表 —— 感染（病毒感染后状态、HIV、梅毒、脑炎、传染性单核细胞增多症后的长期疲劳）；代谢与内分泌（甲亢与甲减两侧、低钠、高钙、低血糖、尿毒症、肝性脑病、肾上腺皮质功能不全）；药物与物质（镇静催眠药、抗胆碱能药、抗组胺药、抗精神病药、皮质类固醇、抗帕金森药、酒精与戒断、以及撤药后的反应）；神经（癫痫、早期痴呆、帕金森病前驱期、多发性硬化、重症肌无力）；阻塞性睡眠呼吸暂停；贫血；含副肿瘤综合征在内的恶性病；以及抑郁、焦虑、躯体症状障碍与创伤相关障碍。这张表里没有任何一项能被「体检正常」排除。
另两条古典自记。方后注「中病，勿更服」—— 中病即止，不再服；把停止规则写进制法，比读者预期的少见，本库把它当作记录的一部分而不是修辞。同一条注释还说「大便当如漆」：粪便应当变黑如漆。今天黑便在被证明是别的原因之前，是上消化道出血的警示症状；铁剂、铋剂与某些食物同样造成黑便。任何情况下出现粪便颜色改变，是要问医生的一件事，不是等着过去的「预期反应」。
药物本身：百合是百合属植物的肉质鳞叶，在许多菜系里是食物；而**百合属对猫有严重肾毒性** —— 猫不能用来推断人该怎么用，但养猫的家庭应当知道。生地黄汁与熟地黄不是同一物，不可互替。孕期与哺乳期没有充分的人体安全性数据。中文文献里这方用于失眠与情绪不适的临床观察数量不大、方法学质量有限；本库如实记「研究存在」，不记「疗效已被确立」。