A practical guide to Fu Ping: what it is, how Traditional Chinese Medicine uses it, the classical formulas it appears in, and who should be careful with it.
Last reviewed Oct 28, 2026| Latin Name | Spirodelae Herba |
|---|---|
| Chinese Name & Pinyin | 浮萍 · Fu Ping |
| Medicinal Part | Whole herbs |
| The item | Fu Ping is the dried whole floating duckweed plant, used raw. Spirodela (Zi Ping) and Jing Jie are not this herb. It suits steeping or being added late in a decoction. |
| Nature and channels | Acrid, cold. Enters the Lung and Bladder. Acrid cold disperses wind-heat, brings out rashes, and promotes urination. |
| Pharmacopoeia line | Disperses wind-heat. Brings out rashes. Promotes urination. Used for wind-heat surface patterns, itchy skin, a slow-coming rash, mild edema, and difficult urination. |
| Pattern cues | Wind-heat itchy skin. A slow-coming rash. Mild edema. Scanty dark urine. |
| In this article | Fu Ping versus Jing Jie and Zi Ping. Dispersing wind-heat versus promoting urination. Why the dose is small and the herb is added late. Why cold digestion and wind-cold are cautions. Who should skip it. |
Fu Ping (浮萍; Fú Píng; Latin: Lemna minor; English: common duckweed) is the dried whole plant of a tiny floating water herb gathered in summer, used raw with no special processing. It is acrid and cold, enters the Lung and Bladder channels, and its core actions are to disperse wind-heat from the surface and bring out rashes, and to promote urination and drain water-dampness. It is a light, floating herb. The usual amount is 3–9 g. Because it is light and airy, it suits steeping in boiling water as a tea, or being added later in a decoction so it is not boiled long.
It is not Jing Jie. Schizonepeta is slightly warm, pungent, entering the Lung and Liver channels; it is a neutral surface herb that disperses both wind-cold and wind-heat, and is better at bringing out rashes and easing early sores. Fu Ping is cold and clearing, focused on wind-heat and water retention. It is not Zi Ping. Spirodela looks similar but has deep-purple undersides and larger fronds. Use caution in pregnancy and nursing. People with cold, weak digestion — stomach pain, loose stools — should not self-use. People with wind-cold, marked chills, clear runny nose, should not self-use. A rash already fully out, or bright-red hot excess, is not a fit.
It is used most often for three patterns:
Acrid and cold, it is not a daily "surface duckweed" to keep increasing. Scattering when there is no wind-heat, or draining when there is no water retention, consumes the Lung qi and weakens the Spleen.
When wind-heat attacks the surface, or water-dampness is retained below, itchy skin, a slow-coming rash, mild fever, and scanty dark urine are common. Fu Ping is acrid and cold. It scatters, brings rashes out, and drains water, which is why it appears in Fu Ping Wan–type formulas for wind-heat-damp skin itching, and in Shuang Jie San–type formulas for surface-interior patterns. It floats more than it holds. A cold weak stomach and spleen, with no heat, get worse if more is added.
Fu Ping is not a catch-all surface or water herb. In cold, weak digestion, wind-cold, or pregnancy, using it alone is a poor match. Whether it belongs in a formula, and at what dose, should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.
Identification & Quality Standard
Spirodelae Herba
Botanical Origin
The dried whole herb of Spirodela polyrhiza (L.) Schleid. (Lemnaceae).
Production Regions
Produced nationwide, more in Hubei, Jiangsu.
Quality Requirements
Superior is green, purple on underside, clean.
Flat suborbicular, 2~5mm diameter. Upper surface gray-green, with several radiating veins; lower surface purple-green, with 5~11 fine roots. Light texture.
Fu Ping grows across freshwater areas nationwide — north and south both produce it, and leaf size and underside color vary a little by region. Traditional sources and industry experience weigh some regions more, though quality also depends on variety, harvest timing, processing, and storage.
Good-quality Fu Ping usually looks like this:
The raw and processed forms look nearly alike, since no special processing is used. Watch out for the look-alike Zi Ping (spirodela) — it looks similar but is often deep purple underneath with larger fronds. Easy to tell apart with care.
Acrid; ColdLung
Fu Ping has a clear paper trail in Chinese herbal literature. A few highlights:
Different generations of physicians read Fu Ping a little differently. Some stressed its wind-heat-dispersing role for surface colds. Others emphasized its urination-promoting role for retained water-dampness. Still others focused on its rash-bringing-out scope, noting it fits only a rash that is slow to come out — not one already fully out or with bright-red, hot excess. These differences show Fu Ping is not a cure-all, and its use must fit the pattern.
This evolution is a good reminder of a core idea in traditional Chinese medicine: herbs are chosen to match the person, not just the symptom.
Traditional Functions
Disperses wind-heat, promotes measles eruption, promotes urination.
What it is: The first core use of Fu Ping is to disperse wind-heat from the Lung channel and push surface invaders out through the skin.
When it was used: Traditionally for wind-heat surface patterns — a light fever, chill on exposure to wind, itchy skin, or a rash that is slow to come out.
Common partners: Often paired with Bo He or Jing Jie to strengthen the wind-heat-dispersing effect; for a slow-coming rash, with Chan Tui or Niu Bang Zi.
Who should not self-use: People with wind-cold — marked chills, light fever, clear runny nose — should avoid it on their own, since Fu Ping is cold and dispersing.
What it is: The second core use focuses on opening the Bladder and draining lower-body water-dampness.
When it was used: Traditionally for retained water-dampness — mild swelling, difficult urination, or scanty dark urine from damp-heat settling below.
Common partners: Often paired with Fu Ling or Ze Xie to strengthen the water-draining effect; for damp-heat difficult urination, with Che Qian Zi or Hua Shi.
Who should not self-use: People with cold, weak digestion — stomach pain, diarrhea, loose stools — should avoid it on their own, since Fu Ping is cold.
The most common pairing is Fu Ping with Bo He. Fu Ping is pungent, clears, and disperses, focusing on surface wind-heat; Bo He is pungent-cool and soothes the surface, focusing on Lung-channel wind-heat. Together they reinforce each other's wind-heat-dispersing, invader-pushing effect — a fit for wind-heat itchy skin, a slow-coming rash, or a light fever with chill on exposure to wind.
Like most pairings, this should be matched to the person, not copied from a list. It belongs in the hands of a practitioner.
Modern research offers useful context, but Traditional Chinese Medicine prescribes on whole-pattern diagnosis rather than isolated compounds.
Modern studies have detected several groups of compounds in Fu Ping:
One important point: detecting a compound in a plant does not mean that compound produces the same effect in the human body. Lab chemistry and human response are two different things.
Research so far is mostly at the early laboratory stage. What has been observed:
These are promising early findings, not proven human benefits. Human clinical research has not yet reached a firm conclusion.
It is important to read the research honestly. Four limits stand out:
Jing Jie is the herb Fu Ping is most often compared with. They share quite a lot:
Despite the similarities, the two herbs differ in a few practical ways:
Fu Ping leans more toward scattering wind-heat and promoting urination, while Jing Jie leans toward dispelling all kinds of wind and bringing out rashes and sores. Both can be used for wind-driven skin discomfort, but they are not freely interchangeable.
How it is built: In this formula, Fu Ping is the main herb (sovereign), dispersing wind-heat and clearing damp. It is joined by Fang Feng and Bai Ji Li, together dispelling wind and easing itching. The herbs work together to both scatter the invader and clear damp — using Fu Ping alone cannot cover the dual need to dispel wind and clear, and its effect is too mild by itself.
Traditional use: This formula was used for wind-heat-damp skin discomfort — itching, hives, and skin issues — along with mild retained water and difficult urination.
Modern note: Modern use should go through proper assessment — do not self-apply just because the name sounds skin-related.
How it is built: In this formula, Fu Ping is a supporting herb (assistant), scattering surface invaders and promoting urination. It is joined by Ma Huang, Bo He, and Zhi Zi, together resolving the surface and clearing the interior. The herbs work together to both scatter the surface invader and drain interior damp — using Fu Ping alone cannot cover the surface-interior need, and its strength is not enough.
Traditional use: This formula was used for wind-heat surface patterns combined with retained interior water — fever and chill on exposure to wind, plus difficult urination and mild swelling.
Modern note: Modern use should go through proper assessment — do not self-apply just because the name sounds cold-related.
A formula combines several herbs to create a whole effect. This is different from using a single herb in one key way:
A gentle, everyday way to meet Fu Ping:
The raw and processed forms of Fu Ping differ little — both are dried whole plants, with no special processing. Because Fu Ping is light and airy, it suits steeping in boiling water as a tea, or being added later when simmered with other herbs, so it is not boiled too long and its active parts are not lost.
For a home decoction, rinse the herbs, add water, soak for 10 minutes, bring to a boil, then simmer on a low heat for about 15 minutes; as a tea, simply steep in boiling water.
Remember that different forms are not directly convertible — slices, extracts, and prepared medicines differ in dose and effect.
In traditional prescriptions, a common dose of Fu Ping is about 3 to 9 g. The food-style dose is about 1 to 3 g, below the medicinal dose.
Fu Ping is not meant for long-term, continuous use. A general course is no more than one week. Pregnant women, nursing mothers, children, and people with liver or kidney concerns should check with a practitioner or pharmacist before use.
What deserves attention here is drug interaction:
Side effects are usually mild. Taking too much may cause stomach discomfort, such as nausea or mild diarrhea.
If you notice clear discomfort, allergic signs such as a rash, itching, or trouble breathing, ongoing vomiting, confusion, or symptoms that worsen quickly, stop use and seek medical attention promptly.
Medical Disclaimer — This article is provided for educational purposes only and describes traditional Chinese medicine concepts. It is not medical advice, and it is not intended to diagnose, treat, cure or prevent any disease. Always consult a qualified practitioner before using any herb, particularly if you are pregnant, nursing, taking medication or managing a diagnosed condition.
