（《本经》下品）
【校正】并入《图经》紫背龙牙。
【释名】蛇衔（《本经》）、威蛇（大明）、小龙牙
恭曰∶陶氏本草作蛇合，合乃含字之误也。含衔义同。见古本草。
时珍曰∶按刘敬叔《异苑》云∶有田父见一蛇被伤，一蛇衔一草着疮上，经日伤蛇乃去。
田父因取草治蛇疮皆验，遂名曰蛇衔草也。其叶似龙牙而小，背紫色，故俗名小龙牙，又名
紫背龙牙。苏颂《图经》重出紫背龙牙，今并为一。
【集解】《别录》曰∶蛇含出益州山谷，八月采，阴干。
弘景曰∶蛇衔处处有之。有两种，并生石上，亦生黄土地。当用细叶有黄花者。
颂曰∶出益州，今近处亦有。生土石上，或下湿地。蜀中人家亦种之，辟蛇。一茎五叶
或七叶。有两种。八月采根阴干。
《日华子》云∶茎叶俱用。五月采之。又曰∶紫背龙牙，生蜀中，春夏生叶，采无时。
时珍曰∶此二种∶细叶者名蛇衔；大叶者名龙衔。龙衔亦入疮膏用。
曰∶蛇衔只用叶晒干，勿犯火。根茎不用。勿误用有 尖叶者，号竟命草，其味酸涩。
误服令人吐血不止，速服知时子解。
【气味】苦，微寒，无毒。权曰∶有毒。颂曰∶紫背龙牙∶辛，寒，无毒。
【主治】惊痫。寒热邪气，除热，金疮疽痔，鼠 恶疮头疡（《本经》）。疗心腹邪气，
腹痛湿痹，养胎，利小儿（《别录》）。
敷蛇虺蜂毒（大明）。
紫背龙牙∶解一切蛇毒。治咽喉中痛，含咽之便效（苏颂）。
【发明】藏器曰∶蛇含治蛇咬。今以草纳蛇口中，纵伤人亦不能有毒也。种之，亦令无
蛇。颂曰∶古今治丹毒疮肿方通用之。《古今录验》治赤疹，用蛇衔草，捣极烂敷之即瘥。
赤疹由冷湿搏于肌中，甚即为热，乃成赤疹。天热则剧，冷则减是也。
时珍曰∶按∶葛洪《抱朴子》云∶蛇衔膏连已断之指。今考葛洪《肘后方》载蛇衔膏云∶
治痈肿瘀血，产后积血，耳目诸病，牛领马鞍疮。用蛇衔、大黄、附子、芍药、大戟、细辛、
独活、黄芩、当归、莽草、蜀椒各一两，薤白十四枚。上为末，以苦酒淹一宿，以猪膏二斤，
七星火上煎沸，成膏收之。每温酒服一弹丸，日再服。病在外，摩之敷之；在耳，绵裹塞之；
在目，点之。若入龙衔藤一两，则名龙衔膏也。所谓连断指者，不知即此膏否？
【附方】旧三，新一。
产后泻痢∶小龙牙根一握，浓煎服之甚效，即蛇含是也。（《斗门方》）
金疮出血∶蛇含草捣敷之。（《肘后方》）
身面恶癣∶紫背草，入生矾研。敷二、三次断根。（《直指方》）
蜈蚣蝎伤∶蛇衔， 敷之。（《古今录验》）
(Recorded in the Lower Grade of *Shennong Bencao Jing*)
[Correction] Merged with *Zibei Longya* (Purple-backed Dragon's Tooth) from *Tujing*.
[Names] Shehan (*Benjing*), Weishe (*Daming*), Xiaolongya.
Tao Hongjing stated: Tao's materia medica writes "Shehe"; "He" is a typo for "Han". "Han" and "Xian" have the same meaning. See ancient materia medica.
Li Shizhen stated: According to Liu Jingshu's *Yi Yuan*: A farmer saw one snake injured, and another snake brought a herb and placed it on the wound. After a day, the injured snake left.
The farmer thus collected this herb to treat snake bites, all of which were effective, so he named it Shehan Cao (Snake-bite Herb). Its leaves resemble those of Longya but are smaller, with a purple back, hence commonly called Xiaolongya, also known as Zibei Longya. Su Song repeated the entry for Zibei Longya in *Tujing*; now they are merged into one.
[Collection] *Bielu* states: Shehan grows in the valleys of Yizhou; harvested in August, dried in the shade.
Hongjing stated: Shehan grows everywhere. There are two types, both growing on rocks or yellow earth. The type with fine leaves and yellow flowers should be used.
Song stated: Grows in Yizhou, now also found nearby. Grows on soil/rocks or in damp lowlands. People in Shu also plant it to repel snakes. One stem has five or seven leaves. There are two types. Harvest roots in August, dry in shade.
*Rihua Zi* states: Stems and leaves are both used. Harvest in May. Also states: Zibei Longya grows in Shu, produces leaves in spring and summer, harvest time is indefinite.
Li Shizhen stated: Of these two types: the one with fine leaves is named Shehan; the one with large leaves is named Longxian. Longxian is also used in wound ointments.
A certain author stated: Only use the leaves of Shehan, dried without fire. Roots and stems are not used. Do not mistakenly use the variety with pointed leaves, known as Jingming Cao, which tastes sour and astringent.
Accidental ingestion causes continuous hematemesis; quickly consuming Zhizishi can detoxify it.
[Flavor and Properties] Bitter, slightly cold, non-toxic. Lei Xiao stated: Toxic. Song stated: Zibei Longya: Pungent, cold, non-toxic.
[Indications] Jingxian (Convulsions due to fright), pathogenic factors of cold and heat, clearing heat, Jinchuang (metal weapon wounds), Ju (carbuncles), hemorrhoids, Shulou (scrofula) and malignant ulcers of the head (*Benjing*). Treats pathogenic factors in the heart and abdomen, abdominal pain with dampness and bi-syndrome, nourishing the fetus, benefiting children (*Bielu*).
Apply externally for venom from snakes, vipers, and bees (*Daming*).
Zibei Longya: Resolves all snake venoms. Treats throat pain; holding it in the mouth and swallowing brings immediate relief (Su Song).
[Elucidation] Canger stated: Shehan treats snake bites. Now, placing the herb in the snake's mouth prevents toxicity even if bitten. Planting it also keeps snakes away. Song stated: It is commonly used in ancient and modern formulas for treating erysipelas and swelling. *Gujin Luyan* treats Chi Zhen (red rash) by using Shehan Cao, pounded to a pulp and applied, resulting in immediate recovery. Chi Zhen occurs when cold-dampness combats within the muscles, turning into heat, forming red rashes. Symptoms worsen in hot weather and improve in cold.
Li Shizhen stated: According to Ge Hong's *Baopuzi*: Shehan Gao (Ointment) can reconnect severed fingers. Examining Ge Hong's *Zhouhou Fang*, the recipe for Shehan Gao states: Treats abscesses, blood stasis, postpartum retained blood, ear and eye diseases, and saddle sores on cattle. Use Shehan, Dahuang, Fuzi, Shaoyao, Daji, Xixin, Du Huo, Huangqin, Danggui, Mangcao, and Shujiao, each 1 liang, and Xiebai 14 pieces. Grind the above into powder, soak in vinegar overnight, then simmer in 2 jin of lard over a "Seven Star" fire until boiling, collect as ointment. Take one pill-sized dose with warm wine, twice daily. For external lesions, massage and apply; for ears, wrap in cotton and insert; for eyes, instill drops. If Longxian Teng is added (1 liang), it is named Longxian Gao. The claim about reconnecting severed fingers—whether this is that ointment is unknown.
[Attached Formulas] Three old, one new.
Postpartum diarrhea and dysentery: One handful of Xiaolongya root, decocted strongly and taken; very effective. This is Shehan. (*Doumen Fang*)
Metal weapon wounds with bleeding: Pound Shehan Cao and apply externally. (*Zhouhou Fang*)
Malignant tinea on body and face: Zibei Cao mixed with raw Mingfan (alum), ground together. Apply two or three times to eradicate the root. (*Zhizhi Fang*)
Centipede and scorpion bites: Apply Shehan Cao. (*Gujin Luyan*)