（《纲目》）
【集解】时珍曰∶生湖泽中，长二、三尺，状如茅、蒲之类。
【气味】（缺）
【主治】妇人白带，煎汤服。又主好嗜干茶不已，面黄无力，为末，和炒脂麻不时干
嚼之（时珍）。
（《本经》中品）
【释名】水花《本经》、水白《别录》、水苏《别录》、水廉《吴普》。
【集解】《别录》曰∶水萍生雷泽池泽。三月采，曝干。
弘景曰∶此是水中大萍，非今浮萍子。《药录》云∶五月有花白色。即非今沟渠所生者。
楚王渡江所得，乃斯实也。
藏器曰∶水萍有三种。大者曰苹，叶圆，阔寸许。小萍子是沟渠间者。《本经》云水萍，
应是小者。
颂曰∶《尔雅》云∶萍， 。其大者苹。苏恭言有三种∶大者曰苹，中者曰荇，小者即
水上浮萍。今医家鲜用大苹，惟用浮萍。
时珍曰∶本草所用水萍，乃小浮萍，非大苹也。陶、苏俱以大苹注之，误矣。萍之与苹，
音虽相近，字却不同，形亦迥别，今厘正之，互见苹下。浮萍处处池泽止水中甚多，季春始
生。或云杨花所化。一叶经宿即生数叶。叶下有微须，即其根也。一种背面皆绿者。一种面
青背紫赤若血者，谓之紫萍，入药为良，七月采之。《淮南万毕术》云∶老血化为紫萍。恐
自有此种，不尽然也。《小雅》“呦呦鹿鸣，食野之苹”者，乃蒿属。陆佃指为此萍
【修治】时珍曰∶紫背浮萍，七月采之，拣净，以竹筛摊晒，下置水一盆映之，即易干
也。
【气味】辛，寒，无毒。《别录》曰∶酸。
【主治】暴热身痒，下水气，胜酒，长须发，止消渴。久服轻身（《本经》）下气。以沐
浴，生毛发（《别录》）。治热毒、风热、热狂， 肿毒、汤火伤、风疹（大明）。捣汁服，主
水肿，利小便。为末，酒服方寸匕，治人中毒。为膏，敷面 （藏器）。主风湿麻痹，香港脚，
打扑伤损，目赤翳膜，口舌生疮，吐血衄血，癜风丹毒（时珍）。
【发明】震亨曰∶浮萍发汗，胜于麻黄。
颂曰∶俗医用治时行热病，亦堪发汗，甚有功。其方用浮萍一两（四月十五日采之），
麻
黄（去根节）、桂心，附子（炮裂，去脐皮）各半两，四物捣细筛。每服一钱，以水一中盏，
生
姜半分，煎至六分，和滓热服，汗出乃瘥。又治恶疾疠疮遍身者，浓煮汁渍浴半日，多效，
此方甚奇古也。
时珍曰∶浮萍其性轻浮，入肺经，达皮肤，所以能发扬邪汗也。世传宋时东京开河，掘
得石碑，梵书大篆一诗，无能晓者。真人林灵素逐字辨译，乃是治中风方，名去风丹也。《诗》
云∶天生灵草无根干，不在山间不在岸。始因飞絮逐东风，泛梗青青飘水面。神仙一味去沉
，采时须在七月半。选甚瘫风与大风，些小微风都不算。豆淋酒化服三丸，铁镤头上也出
汗。其法∶以紫色浮萍晒干为细末，炼蜜和丸弹子大。每服一粒，以豆淋酒化下。治左瘫右
痪，三十六种风，偏正头风，口眼 斜，大风癞风，一切无名风及香港脚，并打扑伤折，及胎
孕有伤。服过百粒，即为全人。此方，后人易名紫萍一粒丹。
【附方】旧七，新十八。
夹惊伤寒∶紫背浮萍一钱，犀角屑半钱，钓藤钩三七个，为末。每服半钱，蜜水调下，
连
消渴饮水∶日至一石者。浮萍捣汁服之。又方∶用干浮萍、栝蒌根等分，为末，人乳汁
和丸梧子大。空腹饮服二十丸。三年者，数日愈。（《千金方》）。
小便不利，膀胱水气流滞。浮萍日干为末。饮服方寸匕，日二服。（《千金翼》）。
水气洪肿∶小便不利。浮萍日干为末。每服方寸匕，白汤下，日二服。（《圣惠方》）。
霍乱心烦∶芦根（炙）一两半，水萍（焙）、人参、枇杷叶（炙）各一两。每服五钱，
入薤白四寸，酒煎温服。（《圣惠方》）。
吐血不止∶紫背浮萍（焙）半两，黄 （炙）二钱半，为末。每服一钱，姜、蜜水调下。
（《
鼻衄不止∶浮萍末，吹之。（《圣惠方》）
中水毒病∶手足指冷至膝肘，即是。以浮萍日干为末。饮服方寸匕良。（《千金方》）。
大肠脱肛∶水圣散∶用紫浮萍为末，干贴之。（危氏《得效方》）
身上虚痒∶浮萍末一钱，以黄芩一钱同四物汤煎汤调下。（《丹溪纂要》）。
风热瘾疹∶浮萍（蒸过焙干），牛蒡子（酒煮晒干炒）各一两，为末。每薄荷汤服一、
二钱，
风热丹毒∶浮萍捣汁，遍涂之。（《子母秘录》）。
汗斑癜风∶端午日收紫背浮萍晒干。每以四两煎水浴，并以萍擦之。或入汉防己二钱亦
可。（《袖珍方》）
少年面 ∶《圣惠方》∶用浮萍日 之，并饮汁少许。《普济方》∶用紫背萍四两，防
己一两，煎浓汁洗之。仍以萍于斑 上热擦，日三、五次。物虽微末，其功甚大，不可小看。
（《普济方》）。
粉滓面 ∶沟渠小萍为末。日敷之。（《圣惠方》）。
大风疠疾∶浮萍草三月采，淘三、五次，窨三、五日，焙为末，不得见日。每服三钱，
食前温酒下。常持观音圣号。忌猪、鱼、鸡、蒜。又方∶七月七日，取紫背浮萍（日干为末）
半升，入好消风散五两。每服五钱，水煎频饮，仍以煎汤洗浴之。（《十便良方》）。
疮入目∶浮萍阴干为末，以生羊子肝半个，同水半盏煮熟，捣烂绞汁，调末服。甚者，
不过一服；已伤者，十服见效。（危氏《得效方》）。
弩肉攀睛∶青萍少许，研烂，入片脑少许，贴眼上效。（危氏《得效方》）。
毒肿初起∶水中萍子草，捣敷之。（《肘后方》）。
发背初起，肿 赤热。浮萍捣和鸡子清贴之。（《圣惠方》）。
杨梅疮癣∶水萍煎汁，浸洗半日。数日一作。（《集简方》）。
烧烟去蚊∶五月取浮萍阴干用之。（孙真人方）
[Compendium of Materia Medica]
[Ji Jie (Collected Explanations)] Li Shizhen said: It grows in lakes and marshes, two to three chi long, resembling plants such as Imperata cylindrica (Mao) and Acorus tatarinowii (Pu).
[Qi Wei (Odor and Flavor)] (Missing)
[Zhu Zhi (Main Indications)] For leukorrhea in women, decoct in water and take. Also indicated for excessive craving for dry tea, sallow complexion, and weakness; grind into powder, mix with fried sesame seeds, and chew occasionally (Li Shizhen).
(Shennong Bencao Jing, Middle Grade)
[Shi Ming (Explanation of Names)] Shuihua (Water Flower) [Benjing]; Shuibai (Water White) [Bielu]; Shuishu (Water Perilla) [Bielu]; Shuilian (Water Cleanse) [Wu Pu].
[Ji Jie (Collected Explanations)] The Newly Revised Classic (Bielu) states: Water duckweed grows in the ponds and marshes of Lei Ze. Harvest in March and sun-dry.
Tao Hongjing said: This is the large duckweed found in water, not the small floating duckweed (Fupingzi) used today. The Yaolu records that it has white flowers in May. Thus, it is not the kind growing in ditches today. What King Chu obtained while crossing the river was the fruit of this plant.
Sun Zangqi said: There are three types of water duckweed. The large one is called Ping (Nymphaea tetragona), with round leaves about one cun wide. The small duckweed is found in ditches. The "Shui Ping" mentioned in the Benjing should refer to the smaller type.
Su Song stated: The Erya says: "Ping, ...". The large one is called Ping. Su Gong said there are three kinds: the large one is Ping, the medium one is Xing (Ottelia alismoides), and the small one is the floating duckweed on water. Currently, physicians rarely use the large Ping, only using Fuping.
Li Shizhen said: The Shui Ping used in materia medica texts is the small floating duckweed, not the large Ping. Tao Hongjing and Su Gong both annotated it as the large Ping, which is an error. Although Ping and Ping sound similar, their characters differ, and their forms are distinct. I hereby correct this, cross-referencing under the entry for Ping. Floating duckweed is abundant in still waters of ponds and marshes everywhere, appearing in late spring. Some say it transforms from willow catkins. One leaf produces several new leaves overnight. Fine roots hang beneath the leaves. One variety is green on both sides. Another variety is green on top and purple-red like blood underneath, called Zi Ping (Purple Duckweed), which is superior for medicinal use; harvest in July. The Huainan Wanbi Shu states: Old blood transforms into purple duckweed. This may be a specific belief, not entirely accurate. The phrase "The deer call yoyo, eating the ping in the wild" from the Xiao Ya refers to a plant in the Artemisia genus. Lu Dian identified it as this duckweed, which is incorrect.
[Xiu Zhi (Processing)] Li Shizhen said: For Zi Bei Fu Ping (Purple-backed Floating Duckweed), harvest in July, select cleanly, spread on a bamboo sieve to dry in the sun, placing a basin of water underneath to reflect light, which facilitates drying.
[Qi Wei (Odor and Flavor)] Acrid, cold, non-toxic. The Bielu adds: Sour.
[Zhu Zhi (Main Indications)] For sudden fever with itching, to promote urination and reduce edema, counteract alcohol intoxication, promote growth of beard and hair, and treat polydipsia. Long-term use lightens the body (Benjing). To direct qi downward. Used for bathing to promote hair growth (Bielu). Treats heat toxins, wind-heat, manic heat disorders, carbuncles, scalds and burns, and wind-rashes (Da Ming). Crushed juice taken internally treats edema and promotes diuresis. Powder taken with wine (one Cun Bi dose) treats poisoning. Applied as a plaster to the face (Zangqi). Treats wind-dampness numbness, beriberi, traumatic injuries, red eyes with corneal opacity, mouth and tongue ulcers, hematemesis, and epistaxis, vitiligo, and erysipelas (Li Shizhen).
[Fa Ming (Elucidation)] Zhu Zhenheng said: The sweating-inducing effect of Fuping surpasses that of Ephedrae Herba (Mahuang).
Su Song said: Folk physicians use it to treat epidemic febrile diseases; it can induce sweating and is quite effective. The prescription uses Fuping (Lemna minor) 1 liang (harvested on the 15th day of the 4th month), Mahuang (Ephedrae Herba, root and nodes removed), Guixin (Cinnamomi Cortex), and Fuzi (Aconiti Lateralis Radix Praeparata, cracked, umbilical skin removed) each 0.5 liang. The four ingredients are pounded fine and sifted. Take 1 qian per dose, decoct with 1 zhuan of water and 0.5 fen of fresh ginger until reduced to 0.6 zhuan, drink hot with the dregs. Recovery occurs when sweat appears. Also, for severe leprosy covering the whole body, boil thick juice and soak/bathe for half a day; often effective. This prescription is very ancient and unique.
Li Shizhen said: Fuping has a light and floating nature, enters the Lung Meridian, and reaches the skin, thus enabling the expulsion of pathogens through sweating. Legend has it that during the excavation of canals in Tokyo (Kaifeng) in the Song Dynasty, a stone stele was unearthed with Sanskrit seal script poetry, which no one could decipher. The Daoist master Lin Lingsu translated it character by character; it was actually a prescription for treating stroke, named Qufeng Dan (Wind-Expelling Pill). The poem reads: "Heaven-born spiritual grass, no root or stem, / Neither in mountains nor on land. / Initially driven by flying catkins chasing the east wind, / Floating stems drift green on the water surface. / One ingredient of immortals removes deep ailments, / Must be harvested around the middle of the seventh month. / Whether paralysis or severe wind-stroke, / Minor winds are insignificant. / Dissolve three pills in bean-sprinkled wine, / Even iron lids will sweat." The method: Dry purple Fuping, grind to fine powder, mix with refined honey to make pills the size of a bullet. Take one pill per dose, dissolved in bean-sprinkled wine. Treats left-sided or right-sided paralysis, thirty-six types of wind disorders, migraine, facial paralysis, severe leprosy, all unnamed wind disorders, beriberi, fractures from trauma, and fetal injury. After taking over a hundred pills, one becomes fully healthy. Later generations renamed this prescription Zi Ping Yi Li Dan (Purple Duckweed Single Pill).
[Fu Fang (Attached Prescriptions)] Seven old prescriptions, eighteen new prescriptions.
Jia Jing Shanghan (Cold Damage with夾惊): Zi Bei Fu Ping 1 qian, Xijiao (Rhinocerotis Cornu) 0.5 qian, Gouteng (Uncariae Ramulus cum Uncis) 3-7 hooks. Grind to powder. Take 0.5 qian per dose, mixed with honey water.
Lian Xiao Ke Yin Shui (Polydipsia drinking one shi daily): Crush Fuping and take the juice. Another prescription: Equal parts dried Fuping and Gualu Gen (Trichosanthis Radix), grind to powder, mix with human milk to make pills the size of wutong seeds. Take 20 pills on an empty stomach with warm water. Cures cases lasting three years within a few days. (Qianjin Fang).
Xiao Bian Bu Li (Difficulty in urination due to bladder water qi stagnation): Sun-dry Fuping, grind to powder. Take one Cun Bi dose with water, twice daily. (Qianjin Yi).
Shui Qi Hong Zhong (Severe edema due to water qi): Difficulty in urination. Sun-dry Fuping, grind to powder. Take one Cun Bi dose with warm water, twice daily. (Shenghui Fang).
Huo Luan Xin Fan (Cholera with restlessness): Lu Gen (Phragmitis Rhizoma, roasted) 1.5 liang, Shui Ping (roasted), Renshen (Ginseng Radix et Rhizoma), Pipay Ye (Loquat Leaf, roasted) each 1 liang. Take 5 qian per dose, add Xiebai (Allii Macrostemonis Bulbus) 4 cun, decoct in wine and take warm. (Shenghui Fang).
Tu Xue Bu Zhi (Unremitting hematemesis): Zi Bei Fu Ping (roasted) 0.5 liang, Huang Qin (Scutellariae Radix, roasted) 2.5 qian. Grind to powder. Take 1 qian per dose, mixed with ginger and honey water. (Shengji Zonglu).
Bi Nie Bu Zhi (Unremitting epistaxis): Blow Fuping powder into the nose. (Shenghui Fang).
Zhong Shui Du Bing (Water toxicity disease): Coldness of fingers/toes extending to knees/elbows indicates this condition. Sun-dry Fuping, grind to powder. Take one Cun Bi dose with water. Effective. (Qianjin Fang).
Da Chang Tuo Gang (Rectal prolapse): Shui Sheng San: Apply Zi Fu Ping powder dry to the affected area. (Wei Shi De Xiao Fang).
Shen Shang Xu Yang (Itching due to deficiency): Fuping powder 1 qian, Huang Qin (Scutellariae Radix) 1 qian. Decoct together with Si Wu Tang (Four Substances Decoction) and take the liquid. (Danxi Zuanyao).
Feng Re Yin Zhen (Wind-heat hives): Fuping (steamed then dried) and Niubang Zi (Arctii Fructus, boiled in wine, sun-dried, stir-fried) each 1 liang. Grind to powder. Take 1-2 qian with mint tea.
Feng Re Dan Du (Wind-heat erysipelas): Crush Fuping and apply juice to the affected area. (Zimu Milu).
Han Ban Dian Feng (Sweat spots and vitiligo): Collect Zi Bei Fu Ping on Dragon Boat Festival (5th day of 5th lunar month), sun-dry. Boil 4 liang in water for bathing, and rub the herb on the skin. Alternatively, add Han Fang Ji (Stephaniae Tetrandrae Radix) 2 qian. (Xiuzhen Fang).
Shao Nian Mian Ban (Facial freckles in youth): Shenghui Fang: Sun-dry Fuping, grind to powder, and drink some juice. Puji Fang: Zi Bei Ping 4 liang, Fang Ji (Stephaniae Tetrandrae Radix) 1 liang. Decoct thick juice for washing. Rub Fuping hot on the spots 3-5 times daily. Though the herb is common, its efficacy is great; do not underestimate it. (Puji Fang).
Fen Zi Mian Ban (Powder-like facial spots): Grind small duckweed from ditches to powder. Apply daily. (Shenghui Fang).
Da Feng Li Ji (Severe leprosy): Harvest Fuping grass in March, wash 3-5 times, store in a pit for 3-5 days, dry and grind to powder, avoiding sunlight. Take 3 qian per dose before meals with warm wine. Chant the name of Guanyin. Avoid pork, fish, chicken, and garlic. Another prescription: On the 7th day of the 7th lunar month, take Zi Bei Fu Ping (sun-dried powder) 0.5 sheng, mix with Hao Xiaofeng San (Excellent Wind-Expelling Powder) 5 liang. Take 5 qian per dose, decoct in water and drink frequently, also bathe with the decoction. (Shibian Liangfang).
Chuang Ru Mu (Ulcer entering the eye): Yin-dry Fuping, grind to powder. Take half a raw sheep liver, cook with half a zhuan of water until done, pound and squeeze juice, mix with powder and take. Severe cases heal in one dose; injured cases show improvement in ten doses. (Wei Shi De Xiao Fang).
Nu Rou Pan Jing (Pterygium): Small amount of Qing Ping, pound to paste, add a little Bing Pian (Borneolum Syntheticum), apply to the eye. Effective. (Wei Shi De Xiao Fang).
Du Zhong Chu Qi (Early stage toxic swelling): Crush aquatic duckweed and apply externally. (Zhouhou Fang).
Fa Bei Chu Qi (Early stage back abscess), red, swollen, hot: Crush Fuping, mix with egg white, and apply. (Shenghui Fang).
Yang Mei Chuang Xuan (Syphilis/Chancre): Decoct water duckweed, soak/wash for half a day. Do once every few days. (Jijian Fang).
Shao Yan Qu Wen (Smoke to repel mosquitoes): Use Yin-dried Fuping collected in May. (Sun Taoren Fang)