泻热利痰、凉惊。
甘凉清心解热。利痰凉惊。通窍辟邪。治中风入脏。惊痫口噤。（心热则火自生焰、肝
热则
木自生风、风火相搏、胶痰上壅、遂致中风不语、按中风、真中者少、类中者多、中脏者重
、多滞九窍、中腑者轻、多着四肢、若外无六经形证、内无便溺阻隔、为中经络、为又轻、
初宜顺气开痰、继宜养血活血、不宜颛用风药、大抵五脏皆有风、而犯肝者为多、肝属风木
而主筋、肝病不能荣筋、故有舌强口噤、 斜瘫痪、不遂不仁等证、若口开为心绝、手撒为
脾绝、眼合为肝绝、遗尿为肾绝、吐沫鼻鼾为肺绝、发直头摇、面赤如妆、汗缀如珠者、皆
不治、或止见一证、犹有可治者。）小儿胎毒痰热诸病。发痘堕胎。东垣曰。牛黄入肝治筋
。中风入脏者。用以入骨追风。若中腑中经者误用之。反引风入骨。如油入面。莫之能出。
（今世中风、有平素积虚、而一时骤脱者、景岳以非风名之、尤忌用此。）牛有黄。必多吼
唤
。以盆水承之。伺其吐出。迫喝即堕水。名生黄。如鸡子黄大。重叠可揭。（时珍曰∶牛有
病、在心肝胆之间凝结成黄、故还以治心肝胆之病、经疏云∶牛食百草、其精华凝结成黄、
犹人之有内丹、故能散火、消痰、解毒、为世神物、或云牛病乃生黄者、非也。）轻虚气香
者良。（观此、则非病乃生黄矣。）杀死。角中得者。名角黄。心中者。名心黄。肝胆中者。
名肝胆黄。成块成粒。总不及生者。但磨指甲上。黄透指甲者为真。（骆驼黄易得、能乱真
。）产陕西者最胜。广中者力薄。得牡丹、菖蒲良。人参为使。恶常山、地黄、龙胆、龙骨
。
To drain heat, resolve phlegm, and cool the liver to extinguish wind (calm convulsions).
Sweet and cool in nature, it clears the Heart, dissipates heat, resolves phlegm, calms convulsions, opens orifices, and expels evil pathogens. It treats stroke with pathogen entering the Zang organs, and epilepsy with jaw clenching. (When the Heart is hot, fire generates flames spontaneously; when the Liver is hot, wind generates spontaneously. Wind and fire contend with each other, causing sticky phlegm to surge upward and obstruct, leading to aphasia due to stroke. Generally speaking, among cases of stroke, those truly caused by external wind are few, while those classified as "stroke-like" (internal injury) are many. When the pathogen enters the Zang organs, the condition is severe, often blocking the nine orifices; when it enters the Fu organs, the condition is mild, often affecting the four limbs. If there are no exterior manifestations of the Six Channels and no internal obstruction of urination or defecation, it is classified as stroke involving the collaterals and meridians, which is even milder. Initially, one should regulate Qi and open phlegm; subsequently, one should nourish blood and invigorate blood circulation. One should not exclusively use wind-expelling herbs. Broadly speaking, wind can affect all five Zang organs, but the Liver is most frequently affected. The Liver belongs to Wind-Wood and governs the sinews. Liver disease fails to nourish the sinews, resulting in symptoms such as stiff tongue, jaw clenching, hemiplegia, paralysis, limb dysfunction, and numbness. If the mouth is open, it indicates Heart Qi exhaustion; if hands are limp, it indicates Spleen Qi exhaustion; if eyes are closed, it indicates Liver Qi exhaustion; if enuresis occurs, it indicates Kidney Qi exhaustion; if froth is vomited and snoring is heard, it indicates Lung Qi exhaustion. Cases with straight hair, shaking head, ruddy face like makeup, and beads of sweat are all incurable. However, if only one of these signs is present, there may still be hope for treatment.) It treats various diseases in infants and children related to fetal toxins and phlegm-heat. It induces abortion or promotes the eruption of smallpox. Li Dongyuan stated: Niu Huang enters the Liver meridian to treat sinus conditions. For stroke where the pathogen has entered the Zang organs, Niu Huang is used to enter the bones and pursue wind. If mistakenly used for stroke affecting the Fu organs or meridians, it will instead draw wind into the bones, like oil penetrating flour, from which it cannot be extracted. (In contemporary times, some stroke cases involve sudden collapse due to chronic deficiency, which Zhang Jingyue termed "Non-Wind"; this type particularly contraindicates the use of this herb.) Cattle producing Niu Huang must roar loudly. Water is collected in a basin, waiting for the cattle to spit it out; under pressure and fright, they drop it into the water. This is called "Sheng Huang" (Raw Yellow). It is the size of an egg yolk and can be peeled in layers. (Li Shizhen said: When cattle are ill, yellow matter condenses between the Heart, Liver, and Gallbladder, so it is used to treat diseases of these organs. Miao Xiyun said: Cattle eat hundreds of herbs, and their essence condenses into yellow, similar to humans possessing an inner elixir, thus it can dissipate fire, resolve phlegm, detoxify, and is regarded as a divine substance by the world. Some claim that Niu Huang arises only from illness, which is incorrect.) Light, void, and fragrant quality is superior. (Observing this, we know it does not arise from illness.) Those obtained after slaughter from the horns are called "Jiao Huang" (Horn Yellow); from the heart, "Xin Huang" (Heart Yellow); from the liver and gallbladder, "Gan Dan Huang" (Liver-Gallbladder Yellow). Those formed into lumps or grains are inferior to Sheng Huang. To test authenticity, grind it on a fingernail; if the yellow color penetrates the nail, it is genuine. (Camel bile stones are easily obtained and can counterfeit it.) Those produced in Shaanxi are the best; those from Guangdong are weak in efficacy. It pairs well with Mudan Pi (Moutan Cortex) and Chang Pu (Acori Tatarinowii Rhizoma). Ginseng serves as its guiding herb. It is incompatible with Chang Shan (Dichroae Radix), Dihuang (Rehmanniae Radix), Long Dan Cao (Gentianae Radix), and Long Gu (Fossilia Ossis Mastodi).