FlowersHeat-clearingCleistocalycis Operculati Flos

Shui Weng Hua (Operculate Cleistocalyx Flower Bud)

A practical guide to Shui Weng Hua: what it is, how Traditional Chinese Medicine uses it, the classical formulas it appears in, and who should be careful with it.

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Last reviewed Oct 29, 2026

Quick Facts

Latin NameCleistocalycis Operculati Flos
Chinese Name & Pinyin 水翁花 · Shui Weng Hua
Medicinal PartFlowers
The itemShui Weng Hua is the dried flower bud of Cleistocalyx operculatus, usually used raw. Pei Lan is not this herb. It usually goes into decoctions or light summer teas.
Nature and channelsBitter, slightly sweet, neutral. Enters the Lung and Stomach. It clears summer-heat, drains dampness, digests food, and harmonizes the middle.
Pharmacopoeia lineClears summer-heat and generates fluids. Resolves food stagnation. Traditionally used for external summer fever, chest stuffiness and gastric fullness, thirst, and damp-heat jaundice.
Pattern cuesEarly-summer slight fever and heavy head. Gastric bloating after meals. Sticky mouth and poor appetite. Short dark urine.
In this articleShui Weng Hua versus Pei Lan. Clearing summer-heat versus awakening the spleen. Why it is a light summer herb rather than a daily drink. Why deficiency-cold should skip it.

What Is Shui Weng Hua?

Shui Weng Hua (水翁花; Shuǐ Wēng Huā; Latin: Cleistocalyx operculatus; English: cleistocalyx flower) in the current pharmacopoeia is the dried flower bud of Cleistocalyx operculatus, a myrtle-family evergreen tree, gathered in early summer before the buds open and sun-dried, usually used raw. It is bitter and slightly sweet, and neutral, enters the Lung and Stomach channels, and its core actions are to clear summer-heat and drain dampness, and to digest food and harmonize the middle. It usually goes into decoctions or light summer teas. The usual amount is 3–10 g. It needs no special handling in a decoction. In light home use it is often steeped with a little rice water as a tea.

It is not Pei Lan. Pei Lan is acrid, neutral, and aromatic; it awakens the spleen and opens damp turbidity, while Shui Weng Hua leans more toward clearing summer-heat and digesting food. A deficiency-cold constitution that is usually cold in the hands and feet with loose stools is a poor match. A weak spleen and stomach with no food stagnation should not take it on its own. Pregnancy and nursing call for caution.

It is used most often for three patterns:

  • Early-summer contraction of summer-dampness — slight fever, heavy head, chest oppression, short dark urine
  • Food stagnation in the stomach — gastric fullness after meals, poor appetite, sticky mouth
  • Summer heat with thirst and vexation after heavy diet and drink

Bitter, slightly sweet, and neutral, it is not a daily “summer tea” to keep brewing all year. When there is no summer-dampness or food stagnation, long use drains the middle and chills a spleen that was already cold.

When early-summer damp-warmth clogs the chest and stomach, or rich food and drink leave stagnation in the middle, slight fever, heavy head, gastric fullness, and a sticky mouth are common. Shui Weng Hua is bitter, slightly sweet, and neutral. It clears summer-heat, drains dampness, and helps the stomach digest, which is why it appears in Shui Weng Hua Yin (Cleistocalyx Flower Drink)–type formulas. It clears and digests more than it builds. A cold weak spleen and stomach, with no dampness or stagnation, get worse if more is added.

Shui Weng Hua is not a catch-all summer or digestion flower. In a cold weak spleen and stomach, with no summer-dampness or food stagnation, or in pregnancy, using it alone is a poor match. Decoction piece or light tea, and whether it belongs in a formula, should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Shui Weng Hua

Shui Weng Hua: Materia Medica Profile

Identification & Quality Standard

Cleistocalycis Operculati Flos

Botanical Origin

The dried young flower bud of Cleistocalyx operculatus (Roxb.) Merr. et Perry (Myrtaceae).

Production Regions

Primarily produced in the Chinese provinces of Guangdong, Guangxi, Hainan, Yunnan.

Quality Requirements

Superior material is dry, dark brown, fragrant and complete.

Macroscopic Features

Oval or spindle-shaped, 4~6 mm long, 3~4 mm diameter; receptacle campanulate, externally dark brown or brownish-black; calyx lobes connate into a circular cap at top; petals 4; stamens numerous, long; texture light and brittle; aromatic odor; bitter taste.

Main Regions and Quality Identification

Traditional materia medica and industry experience value the Shui Weng Hua of the southern producing areas — such as the Lingnan region — but actual quality also depends on variety, harvest time, processing, and storage. Good-quality Shui Weng Hua appears as dried, fine, small flower buds, green-brown or brown-brown in color, light and crisp in texture, with a faint fresh fragrance, a slightly bitter taste when tried, and no obvious moldy or burnt odor. The common look-alikes are the dried flower buds of other plants of the same family — with larger flowers and fainter fragrance — note the difference.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Bitter, Sweet; CoolLungSpleenStomach

1. Records in Classic Materia Medica

  • Sheng Cao Yao Xing Bei Yao (Qing dynasty): mentions that Shui Weng Hua can "clear summer heat, generate fluids, stop thirst, and regulate sores and scabies."
  • Ben Cao Qiu Yuan: supplements that it can "dissolve bone-food stagnation, clear summer heat, and resolve alcohol toxin."
  • Ling Nan Cai Yao Lu: also carries a record that it can "treat external-contraction fever and damp-heat jaundice."

These records all revolve around Shui Weng Hua's summer-heat-clearing and stomach-harmonizing actions — without exaggerating its effects.

2. How Views of Its Nature Changed

Views among physicians differ somewhat. Some stress its summer-heat-clearing action, mostly for the external summer-dampness discomfort of summer; some lean to its digestion-promoting, stomach-harmonizing action, fitting the stomach-wind discomfort of food accumulation; some hold that its scope is relatively narrow — fitting only those of a damp-heat constitution, while those of a deficiency-cold constitution should not use it long-term. These differences reflect the careful attitude of physicians through the ages — not treating it as a universal drug.

Shui Weng Hua

Core Efficacies & Traditional Applications

Traditional Functions

Clears heat and resolves toxin, dispels summerheat and generates fluids, disperses food stagnation and leaches dampness.

1. First Direction: Clearing Summer Heat

  • Traditional action: clear the summer heat, easing the body discomfort caused by summer dampness.
  • Typical signs: the patterns of external summer-dampness in summer — shown as a slight fever, a dizzy, heavy head, chest oppression and gastric fullness, thirst without wanting to drink much, and short, red urine.
  • Usual combinations: often paired with other summer-heat-clearing or dampness-resolving herbs — such as He Ye and Hua Shi — to strengthen the summer-heat-clearing effect.
  • Who should not self-use: those of a deficiency-cold constitution — usually fearing cold, with cold hands and feet and loose stool — should not self-use Shui Weng Hua alone.

2. Second Direction: Helping Digestion and Harmonizing the Stomach

  • Traditional action: help digestion and harmonize the spleen-stomach digestive function.
  • Typical signs: the patterns of food accumulation — gastric fullness, poor appetite, post-meal indigestion, and a sticky mouth.
  • Usual combinations: often paired with other digestion-promoting herbs — such as Shan Zha and Mai Ya — to strengthen the digestion-promoting action.
  • Who should not self-use: those with spleen-stomach weakness without marked food stagnation should not self-use Shui Weng Hua.

3. Classic Pairing: Shui Weng Hua With Shan Zha

The common pair is Shui Weng Hua with Shan Zha: Shui Weng Hua leans to clearing summer heat and resolving dampness, helping ease the spleen-stomach discomfort of summer dampness; Shan Zha leans to promoting digestion and resolving accumulation, helping ease the problem of food accumulation. Combined, the two coordinate — both clearing summer heat and harmonizing the stomach, and promoting digestion to guide stagnation — fitting the patterns of summer dampness with food accumulation at the same time. This pairing needs the physician's pattern diagnosis — do not pair casually on your own.

Shui Weng Hua

Modern Research

Modern research offers useful context, but Traditional Chinese Medicine prescribes on whole-pattern diagnosis rather than isolated compounds.

1. Main Chemical Constituents

The constituents detected in the plant include volatile oils, flavonoids, and triterpenoids. In in vitro experiments, some flavonoid constituents show a certain antioxidant activity; in animal experiments, research with the Shui Weng Hua extract shows a certain effect on the body-temperature regulation of mice, but the specific mechanism is not yet defined. Currently, no sufficient human clinical data confirms its specific actions in the human body.

2. Current Research Directions

Current research mainly focuses on the isolation of the effective constituents of Shui Weng Hua and the preliminary activity screening:

  • Research shows that its volatile-oil constituents show a certain inhibitory effect on some common pathogenic bacteria in vitro.
  • In experiments, the Shui Weng Hua extract shows a mild regulatory effect on intestinal motility in animal models.

More human studies are still needed to verify its actual effect in daily regulation.

3. Limitations of Current Research

  • Lab results are not clinical efficacy — in vitro and animal results cannot be directly equated with the therapeutic effect in humans; the absorption and metabolism of the drug in the body affect the final action.
  • Extracts and monomers are not the same as traditional slices — the extracts or monomers used in research differ markedly from the daily-used Shui Weng Hua slices in dose and constituent ratio — they cannot be equated directly.
  • Doses and preparation methods vary between studies — the extraction solvents and concentrations differ across studies — the results lack a unified standard and are hard to compare directly.
  • A single component does not define the whole herb — Shui Weng Hua's action is the joint result of many constituents; the activity of a single constituent cannot represent the whole herb's overall effect.

Shui Weng Hua

Comparing Similar Herbs

1. What They Share

Choosing Pei Lan as the similar herb, the two share three points:

  • Both have the main actions of clearing summer heat and resolving dampness.
  • Both are used for the spleen-stomach discomfort patterns of summer dampness.
  • Both often appear in summer food-therapy or light-regulation scenes — and both need the constitution and dose considered in use.

2. The Key Differences: Shui Weng Hua vs. Pei Lan

  • Nature and flavors: Shui Weng Hua is neutral with bitter and slightly sweet flavors — gentle, not overly fierce; Pei Lan is also neutral but with an acrid flavor and an aromatic character. Both are neutral, but the flavor difference leads to different action tendencies.
  • Focus: Shui Weng Hua leans to clearing summer heat, harmonizing the stomach, and promoting digestion — fitting the discomfort caused by summer dampness and food accumulation together; Pei Lan leans to resolving dampness and awakening the spleen — fitting the sticky mouth and thick tongue coating of dampness trapping the spleen-stomach.
  • Qi tendency: Shui Weng Hua belongs to the clearing-draining class — its effect on qi is a gentle regulation, without over-dispersing or over-astringing; Pei Lan belongs to the aromatic dampness-resolving class — its tendency is to awaken the spleen and disperse the dampness-turbidity, helping open the spleen-stomach qi.
  • Best fit: Shui Weng Hua's fitting signs are mostly a slight summer fever, gastric fullness, and post-meal discomfort — with a thin greasy tongue coating and a soft, slightly rapid pulse; Pei Lan's signs are mostly a sticky mouth, bad breath, and a thick greasy tongue coating — with a thick turbid coating and a slow pulse.
  • Not suitable: Shui Weng Hua — not for those of a deficiency-cold constitution or with loose stool without stagnation; Pei Lan — not for those of a yin-deficiency constitution with a dry mouth and tongue and no dampness-turbidity.
  • Use scenes: Shui Weng Hua appears more in daily light regulation — such as summer tea and simple food therapy; Pei Lan appears more in formula combinations — for the spleen-stomach regulation with marked dampness-turbidity.

3. One-Sentence Summary

Simply put, Shui Weng Hua leans toward clearing summer heat, harmonizing the stomach, and promoting digestion to guide stagnation, whereas Pei Lan leans toward resolving dampness, awakening the spleen, and regulating the spleen-stomach qi. Both can be used for the spleen-stomach discomfort of summer dampness, but they are not interchangeable.

Shui Weng Hua

Classical Formulas Containing Shui Weng Hua

Classic Formula 1: Shui Weng Hua Yin (Cleistocalyx-Flower Drink)

Combination logic: In this formula, Shui Weng Hua is the lord, exerting the core action of clearing summer heat and harmonizing the stomach; He Ye is combined to strengthen the summer-heat-clearing effect, and Chen Pi to strengthen the stomach-harmonizing effect. The three work together to solve the spleen-stomach discomfort caused by summer dampness. This herb cannot be used alone, because used alone it is hard to attend to the three needs of clearing summer heat, resolving dampness, and harmonizing the stomach at the same time.

Traditional use: traditionally used for the patterns of external summer-dampness with spleen-stomach food stagnation — shown as a slight fever, dizziness, gastric fullness, and poor appetite.

Modern note: modern clinical use of this formula requires the doctor's pattern diagnosis and standard care — do not self-apply just because the formula name relates to summer regulation; adjust it to your specific pattern.

Classic Formula 2: Qing Shu Xiao Ji Tang (Summer-Heat-Clearing Accumulation-Resolving Decoction)

Combination logic: In this formula, Shui Weng Hua is an assistant, exerting the auxiliary actions of clearing summer heat and promoting digestion; Hua Shi is combined to strengthen the summer-heat-clearing and dampness-benefiting action, Shan Zha to strengthen the digestion-promoting action, and Fu Ling to strengthen the spleen-strengthening action. In this formula, the herb plays the role of coordinating the summer-heat-clearing and digestion-promoting — it cannot be used alone.

Traditional use: traditionally used for the patterns of summer dampness with food accumulation — shown as fever, chest oppression, gastric fullness, and post-meal discomfort.

Modern note: modern clinical use of this formula requires the doctor's pattern diagnosis and standard care — do not self-apply just because the formula name relates to summer heat; the physician must adjust the herbs and doses to the specific pattern.

Formulas vs. Single Herbs

A formula is many herbs acting together, attending to the needs of many patterns through the lord-minister-assistant-courier combination; a single herb cannot simply replicate a full formula's effect, because a single herb's scope of action is limited. The doses and combinations in a formula are holistic — each herb's dose and action have been adjusted and combined; casually splitting or replacing them may break the overall effect. Do not build formulas from online articles, because professional pattern differentiation and dose control are lacking. To be clear: a herb that works in a formula does not mean taking it alone produces the same effect — a formula's action is the synergy of many herbs.

Diet & Daily Home Use

1. Home Tea and Porridge

(1) Shui Weng Hua Dan Zhu Ye Cha (Cleistocalyx-and-Bamboo-Leaf Tea): Shui Weng Hua 3 g, Dan Zhu Ye 3 g, Jing Mi 10 g. Cook the Jing Mi into rice water; after the rice water cools to warm, add the Shui Weng Hua and Dan Zhu Ye and steep 10 minutes. Suited to daily summer-heat clearing — easing mild dizziness and chest oppression. Not for those of a deficiency-cold constitution with loose stool. Suggested: 2–3 times a week, one small cup each time.

(2) Shui Weng Hua Shan Zha Zhou (Cleistocalyx and Hawthorn Porridge): Shui Weng Hua 5 g, Shan Zha 5 g, Da Mi 50 g. First cook the Da Mi into porridge; 10 minutes before it is done, add the Shui Weng Hua and Shan Zha, stir well, and turn off the heat. Suited to summer post-meal indigestion and gastric fullness. Not for those with spleen-stomach weakness without food stagnation. Suggested: once every 1–2 weeks, a small half bowl each time.

2. Decoction and Processing Differences

The raw Shui Weng Hua has no special processing — its odor is light, fitting use in tea or porridge; the processed form is mostly the sun-dried raw product, with the same decocting requirements as other slices — no special handling. Shui Weng Hua needs no pre-boiling, late addition, bag-boiling, or dissolving; for home decoction, it can be put into the pot together with the other food or herbs and boiled. Different forms cannot be converted directly — the dose of the slices differs from the amount used in tea; adjust according to the use scene.

3. Dosage and Course

The common dose in traditional prescriptions is 3–10 g — for medicinal use, follow the doctor's instructions. The food-therapy dose is usually 3–5 g, for daily light regulation. Long-term continuous use is not advised — generally each use should not exceed 7 days; if the symptoms do not ease, consult a physician. Special groups — such as pregnant women, children, and the elderly — need the dose adjusted and should consult a professional.

Shui Weng Hua

Contraindications & Safety Warnings

1. Who Should Avoid It

  • Deficiency-cold constitution — those who usually fear cold, with cold hands and feet and loose stool, should not use it.
  • Pregnancy and breastfeeding — need caution; consult a physician before deciding whether to use it.
  • Children and the elderly — weaker spleen-stomach function — should not self-use.
  • Liver or kidney impairment — weaker drug metabolism — consult a physician before use.
  • Allergy to Myrtaceae plants — may have an allergic reaction to Shui Weng Hua.
  • Those in special treatment — such as chemotherapy or immunotherapy — need to avoid self-use.

2. Interactions and Diet Notes

There is no sufficient evidence of a general "food clash" between ordinary foods, but certain herbs can interact with specific drugs — those on medication should consult a doctor or pharmacist first. The interactions of Shui Weng Hua with anticoagulants, blood-pressure medications, and glucose-lowering medications are not yet defined — if taking such drugs, consult a physician before use. Shui Weng Hua may affect the absorption of some drugs — it is advised to take it 1–2 hours apart from other medications. Some "food-clash" claims lack reliable evidence — no need to worry excessively, but keep the daily diet light.

3. Adverse Reactions and Overdose Risk

The adverse reactions of Shui Weng Hua are currently rare, but an excessive dose may cause mild gastrointestinal discomfort — such as nausea and gastric fullness. If marked discomfort, allergy signs such as a rash and itching, persistent vomiting, breathing difficulty, altered consciousness, or rapidly worsening symptoms appear, stop at once and seek medical care.

Frequently Asked Questions About Shui Weng Hua

What is Shuiwenghua? Is it the same as Jinyinhua or Juhua?
Shuiwenghua is the dried flower bud of Cleistocalyx operculatus, Latin name Cleistocalycis Operculati Flos. It is a common Chinese medicine centered on clearing heat and detoxifying, dispelling summer-heat and generating fluids, and resolving stagnation and draining dampness. Jinyinhua clears heat and detoxifies for external contraction. Juhua disperses wind and clears heat for brightening the eyes. They cannot be used interchangeably in equal amounts. Prescribe as Shuiwenghua. Caution in spleen-stomach deficiency cold.
What are the composition and effects of Shuiwenghua?
Pharmacopoeial name Shuiwenghua, Latin Cleistocalyx operculatus (Roxb.) Merr. et L.M.Perry. Bitter and slightly sweet in taste, cool in nature, enters the Lung, Spleen and Stomach meridians. Functions to clear heat and detoxify, dispel summer-heat and generate fluids, and resolve stagnation and drain dampness. Used for common cold with fever, bacillary dysentery, acute gastroenteritis, and indigestion. Clears heat and dispels summer-heat.
How to choose between raw and processed? Can Jinyinhua replace it?
Flower buds are used raw. Jinyinhua emphasizes external contraction rather than strongly dispelling summer-heat, and cannot replace it in equal amounts. Commercial products are standardized; do not adjust arbitrarily.
What is the dosage of Shuiwenghua? Can it be used daily as a summer-heat-dispelling tea?
Decoction, 15-30g. Modern use requires physician-determined dosage. It is not a year-round "Shuiwenghua tea." Spleen-stomach deficiency cold will be further injured by prolonged use. Fever requires short-term, physician-determined dosage and cannot replace evaluation.
What are the contraindications of Shuiwenghua? Can pregnant women use it?
Not suitable for spleen-stomach deficiency cold. Pregnant women require physician evaluation. Stop if loose stools or abdominal pain occur. Seek immediate medical care for severe fever or high fever.
Can Shuiwenghua clear heat, dispel summer-heat, and generate fluids?
It can assist common cold with fever, bacillary dysentery, acute gastroenteritis, and indigestion. It clears heat and detoxifies, dispels summer-heat and generates fluids, and resolves stagnation and drains dampness, but is not a specific remedy for all fever or all indigestion.
Can Shuiwenghua be taken daily as a summer-heat-dispelling or fluid-generating tea?
Summer-heat can be used short-term in formulas; spleen-stomach deficiency cold will be further injured. The idea that "Shuiwenghua must dispel summer-heat" cannot replace evaluation. Clearing heat and generating fluids requires physician-determined formulation and dosage.
How to choose between Shuiwenghua, Jinyinhua, Juhua, Bohe, and Huoxiang?
Shuiwenghua clears heat and dispels summer-heat while generating fluids, suited to summer-heat. Jinyinhua clears heat and detoxifies for external contraction. Juhua disperses wind and clears heat for brightening the eyes. Bohe disperses wind and dissipates heat for the throat. Huoxiang transforms dampness and resolves summer-heat. Choose Shuiwenghua for dispelling summer-heat; Jinyinhua for external contraction; Juhua for brightening the eyes; Bohe for the throat; Huoxiang for transforming dampness. Pattern differentiation applies, but large doses of Shuiwenghua are contraindicated in spleen-stomach deficiency cold.
How is Shuiwenghua commonly modified? What is a representative usage?
Modifications depend on the pattern. Add Jinyinhua for fever; add Shanzha for indigestion. Specify Shuiwenghua; do not substitute Jinyinhua in equal amounts for dispelling summer-heat.
How to select and store Shuiwenghua?
Choose regular Chinese medicinal materials with intact flower buds. Discard if moldy, damp, or abnormal in odor. Store in a dry place. Purchase "Shuiwenghua"; do not substitute Jinyinhua or Juhua in equal amounts for clearing heat, dispelling summer-heat, and generating fluids.

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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.

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Shui Weng Hua (Operculate Cleistocalyx Flower Bud): Clears heat, resolves toxicity, dispels summer-heat, and generates fluids