duckweed

　　Duckweed is the dried whole plant of Spirodela polyrrhiea (L.) Schleid. It is produced in ponds and swamps all over the country, with Hubei, Jiangsu, Zhejiang, Fujian, Sichuan and other provinces producing the most. Harvest from June to September, remove impurities and dry in the sun. For raw use.

　　[Properties] Pungent, cold. Returns to the lung and bladder meridians.

　　[Efficacy] Produce sweating and relieve surface inflammation, relieve rash and relieve itching, diuresis and reduce swelling.

　　【application】

　　1. Wind-heat cold. This product is pungent and cold, with a light and floating texture. It has the effect of relieving the lungs, causing sweating, and dispersing wind-heat. It is more suitable for wind-heat colds, fever without sweating, etc. It can be used with peppermint, cicada slough, and forsythia suspensa. If you have a cold due to wind-cold, aversion to cold and no sweating, it can also be used together with wind-cold medicines such as cinnamon, rhizome, and Qianghuo.

　　2. Measles is not clear. The pungent powder of this product can dispel wind-heat and relieve superficial rash. It is used for the initial onset of measles and when the rash is not smooth. It is often used with mint, cicada slough, and burdock.

　　3. Rubella itching. This pungent powder has the effect of dispelling wind and relieving itching, and can be used to treat wind-evil stagnant muscle surface and rubella itching. For those who are prone to wind-heat, it is usually used with pungent and cool wind-repelling and anti-pruritic medicines such as cicada slough, mint, and burdock. For those who are prone to wind-cold, it is often used with pungent and warm wind-repelling and anti-pruritic medicines such as fenugreek, saposhnikovia, and Schizonepeta.

　　4. Edema and oliguria. This product can open up lung qi, induce sweating and remove evil spirits, and regulate water channels, diuresis and reduce swelling. Therefore, it is suitable for treating edema, oliguria and wind-heat syndrome. It can be used alone, or used equally with forsythia, forsythia, and wax gourd peel.

　　[Usage and Dosage] Decoction and take 3 to 9 g. Appropriate amount for external use, decoction and dipping.

　　【Usage Note】It should not be used by those with weak symptoms and spontaneous sweating.

　　[Abstract from ancient books]

　　1. "Shen Nong's Materia Medica": "It is mainly used to treat severe heat, itching, water vapor, alcohol, long beard and hair, and quenching thirst. ”

　　2. "Compendium of Materia Medica": "When treating a febrile disease, it may cause sweating. ”

　　3. "Jade Catalpa Medicinal Solution": "It is pungent and cool to relieve symptoms. It can be used to treat plague macules, stroke, paralysis, carbuncle, rash, pruritus, red bayberry, acne, and sweat spots. ”

　　【Modern Research】

　　1. Chemical composition: This product contains flavonoids such as redphyllin and vitexin. In addition, it also contains carotene, lutein, potassium acetate, iodine, brominated fatty acids and other substances.

　　2. Pharmacological effects: Duckweed has a diuretic effect, and its active ingredients are mainly potassium acetate and potassium acetate. Duckweed aqueous extract has a cardiotonic effect and can constrict blood vessels and increase blood pressure. In addition, it has antipyretic and antibacterial effects.

　　3. Clinical research: It is reported that the Shuangzi Baifu Decoction, which is mainly composed of 60g of fresh duckweed, 15g of Lithospermum purpurea, and 30g of fresh white peel, has been used to treat 215 cases of common skin diseases such as acne and eczema through syndrome differentiation and modified medication, and has achieved good results (Heilongjiang Traditional Chinese Medicine, 1998, (2): 7). Guizhi duckweed decoction (15g each of cinnamon twig, atractylodes, saposhnikovia, and coix seed, 10g each of duckweed and saponaria, 20g of kochia chinensis, and 25g of silkworm sand) was used to treat 50 cases of urticaria, with remarkable results (Acta Chinese Medicine, 1998, 26(3): 43).