A practical guide to Lv Dou: 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 | Phaseoli Radiati Semen |
|---|---|
| Chinese Name & Pinyin | 綠豆 · Lv Dou |
| Medicinal Part | Fruits and seeds |
| The item | Lu Dou is the dried ripe seed of the mung bean. Chi Xiao Dou (red adzuki bean) is not this drug. It is usually boiled into soup or porridge. |
| Nature and channels | Cold, sweet. Enters the Heart and Stomach. Cold sweet clears summerheat and resolves heat toxins. |
| Pharmacopoeia line | Clears summerheat and relieves thirst; resolves heat toxins. Used for summer heat with irritability and thirst, and for heat-toxin flares of the skin and gut. |
| Pattern cues | Summer stuffiness. Irritability. Thirst. Boils and red swollen skin. Heat in the gut. |
| In this article | Lu Dou versus Chi Xiao Dou. Clearing summerheat versus resolving toxins. Why a cold body should skip it. Home soup and tea. |
Lu Dou (绿豆; Lǜ Dòu; Latin: Semen Phaseoli Radiati; English: mung bean) is the dried ripe seed of the mung bean plant — a food first, a herb second. It is cold and sweet, enters the Heart and Stomach channels, and its core actions are to clear summerheat, and to resolve heat toxins. It is the gentle, everyday "heat-and-summer" remedy — a bowl of mung bean soup that cools the body without blasting it. The usual amount is 10–30 g as a medicinal piece. It is usually boiled into soup or porridge. External use is not common — it is a taken-by-mouth herb.
It is not Chi Xiao Dou. Red adzuki bean is neutral, sour-sweet, and moves water and swelling; it does not clear summerheat the way mung bean does. It is not a "detox catch-all" either — for real poisoning, seek emergency care; no food or herb replaces a clinic. In a deficiency-cold body — cold hands and feet, loose stools — or during menstruation, using it heavily on your own is a poor match. Severe poisoning, or high fever with confusion, needs urgent care. Do not take it yourself for a long time.
It is used most often for three patterns:
Cold and sweet, it is not a daily "cool-down tea" to keep drinking. Coldness when there is no heat can chill a weak spleen-stomach.
When summerheat attacks from outside, the body feels stuffy, the mind irritable, and the mouth dry; when heat toxin builds from within — rich food, too much drink, or something unwise — the skin flares and the gut heats up. Lu Dou is cold and sweet. It clears and it cools, which is why it appears in Lu Dou Yin (Mung Bean Drink)–type formulas. It cools more than it pushes. In deficiency-cold, with no heat, more makes it worse.
Lu Dou is not a catch-all cool-down or detox herb. In deficiency-cold, during menstruation, or with no heat to clear, using it heavily 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
Phaseoli Radiati Semen
Botanical Origin
The dried ripe seed of Vigna radiata (L.) R.Wilczek (Fabaceae).
Production Regions
Primarily produced in Hubei, Shanxi, Hebei, Anhui, Shandong.
Quality Requirements
Superior is green, full, clean.
Short cylindrical or spherical, 4~6mm diameter. Externally green or dark green, smooth. One side has a white linear hilum. Hard, two cotyledons yellowish-white.
Classic texts and trade experience favor several northern growing provinces, with some cultivation in the south; quality still depends on variety, harvest time, processing, and storage. Good Lu Dou is short and oblong, about 2.5–4 mm long and 2.5–3 mm wide, yellow-green to dark green and glossy, with a white lengthwise hilum on one side, hard, with yellow-white cotyledons inside, a light smell, and a beany taste when chewed. The raw seed is bright and hard; the stir-fried seed is darker yellow, slightly crisper, with a light toasted smell. The common look-alike is fan bean — larger, red-brown or yellow-brown, with a different hilum shape — easy to tell apart.
Sweet; CoolHeartStomach
All the records stay within the summerheat-and-toxin circle.
Some doctors stressed the summerheat-clearing side — summer is the season for it; others stressed the toxin-resolving side — for heat poison from food or medicine; a third group drew the scope — it fits heat-leaning bodies with summerheat or heat toxin, while deficiency-cold bodies should not use it long. Lu Dou is not a universal herb; the pattern decides the use.
Traditional Functions
Clears heat and resolves toxin, relieves summerheat, promotes urination.
(1) Traditional action: clearing summerheat, supporting qi, and relieving vexation and thirst. (2) Typical patterns: in summer heat — irritability, thirst, spontaneous sweating, a stuffy hot feeling, sometimes with scanty dark urine. (3) Usual pairings: Xi Gua Cui Yi (watermelon rind) to strengthen the summerheat clearing; or rice in a mung bean porridge to support qi and the stomach. (4) Not for self-use: deficiency-cold bodies — cold hands and feet, loose stools — and women during menstruation; the cold can add to the chill.
(1) Traditional action: clearing heat toxins from inside the body or from outside sources. (2) Typical patterns: boils and red swollen skin; gut heat after warming medicines or too much drink; mild food-poisoning discomfort like nausea and stomach upset. (3) Usual pairings: Gan Cao (licorice) to strengthen the toxin-resolving and temper the cold; Jin Yin Hua (honeysuckle) for heavier heat toxin. (4) Not for self-use: no obvious heat toxin — no mouth sores, no dry stools — and a weak spleen-stomach; the cold can injure the digestion.
Lu Dou pairs classically with Gan Cao: mung bean is cold and sweet and clears heat toxin and summerheat; licorice is neutral and sweet and harmonizes, tempers the cold, and adds to the toxin-resolving. Together they suit mild food or drink toxicity and summer heat with a touch of toxin — but real poisoning means the clinic first, not this pair alone.
Modern research offers useful context, but Traditional Chinese Medicine prescribes on whole-pattern diagnosis rather than isolated compounds.
Detected in the bean are protein, polysaccharides, dietary fiber, polyphenols (flavonoids, tannins), small amounts of alkaloids, and minerals. In vitro, some polyphenols show antioxidant activity — a dish result. In animal experiments, extracts have shown some effect on inflammatory responses. Human research is still at small-sample observation — no firm conclusion yet.
Current work centers on the active constituents — the antioxidant potential of polyphenols and the possible regulatory effects of polysaccharides. Experiments show some free-radical clearing outside the body, but what happens inside a person is not yet clear. Most work is still at extraction and early screening — human verification is needed.
Nature and flavor: Lu Dou is cold and sweet — it clears and cools, more for heat of the upper body and skin; Chi Xiao Dou is neutral and sour-sweet — it moves water and swelling, more for the lower burner and dampness. Focus: Lu Dou clears summerheat and heat toxin — heat-driven irritability, thirst, skin flares; Chi Xiao Dou moves water, reduces swelling, and drains pus — water stagnation and swelling, and boils with matter. Tendency: Lu Dou sinks and clears heat downward; Chi Xiao Dou drains and moves water downward with a toxin-clearing side. Best fit: Lu Dou for summer irritability and thirst, or mild red swollen skin; Chi Xiao Dou for leg swelling, scanty urine, or boils slow to open. Who should avoid: Lu Dou is wrong for deficiency-cold bodies (cold hands, loose stools); Chi Xiao Dou is wrong for the same bodies and for people with frequent urgent urination — its water-moving is strong. Where you meet them: Lu Dou in summer food remedies — soup, porridge — for short heat care; Chi Xiao Dou in water-moving formulas and swelling care.
In short, Lu Dou clears summerheat and heat toxin; Chi Xiao Dou moves water and reduces swelling. Both can appear in damp-heat care — but they are not stand-ins for each other.
Role of this herb: Lu Dou Yin (Mung Bean Drink) is Lu Dou alone as the monarch — a simple summerheat-and-toxin clearing drink for irritability, thirst, and mild skin heat. There is no supporting cast, so it fits light discomfort only; heavier heat or stronger toxin needs other herbs alongside. Traditional focus: summer heat with vexation and thirst, and mild heat-toxin skin discomfort. Modern note: severe summerheat illness or poisoning means urgent care — never self-apply by name.
Role of this herb: in Lu Dou Gan Cao Tang (Mung Bean and Licorice Decoction), Lu Dou is the monarch and Gan Cao the minister — the bean resolves the heat toxin, the licorice tempers the cold and adds to the clearing. It suits mild food or drink toxicity and gut heat. For real poisoning, this decoction is not the emergency plan — the clinic is. Traditional focus: mild poisoning and gut heat. Modern note: never self-apply by name; seek urgent care for actual poisoning.
A formula is a coordinated team; a single herb cannot copy a full formula's effect. The doses and pairings are designed as a whole, and a herb that works in a formula does not automatically work the same way alone. Do not self-formulate from web articles — the pattern and the dose are the point.
Example 1 — Lu Dou lily porridge: Lu Dou 30 g (soaked 2 hours), Bai He (lily bulb) 10 g, rice 50 g — cooked together into porridge. Fit: summer irritability and dry mouth; 1 small bowl, 1–2 times a week. Not for: deficiency-cold bodies with frequent loose stools. Example 2 — Lu Dou chrysanthemum tea: Lu Dou 20 g boiled soft, then Ju Hua (chrysanthemum) 5 g added and simmered 5 minutes — drink the liquid. Fit: summer heat with mild eye dryness and irritability; 1 small cup, 2–3 times a week. Not for: a weak spleen-stomach prone to bloating. As a medicinal piece, Lu Dou belongs under a practitioner's direction — not an everyday food to overeat.
The raw bean is colder and better for clearing summerheat and toxin; the stir-fried bean is milder and suits a slightly weaker spleen for light care. At home, raw Lu Dou needs soaking 1–2 hours and a longer simmer to soften — no first, last, or wrapped handling; just boil it. Different forms cannot be converted directly — a medicinal dose and a food-use amount are not the same.
The classic medicinal range is 10–30 g; food-use amounts run 20–50 g — larger, but still controlled. Not for long continuous use — a 1–2 week summer course is usually enough. Pregnant women, children, and the elderly consult a practitioner or pharmacist first.
Deficiency-cold bodies — cold hands and feet, loose stools — no long or heavy use; pregnancy and nursing — be cautious with the cold; children and the elderly — weaker digestion, no heavy self-use; liver or kidney impairment — guidance only; allergy to mung bean or other legumes — avoid; people in chemotherapy or on anticoagulants — consult a doctor first.
Lu Dou is cold and may interact with anticoagulants, blood-pressure, and blood-sugar medicines, affecting absorption or metabolism — anyone on such medicines should consult a doctor or pharmacist first. No blanket "food clash" with ordinary foods is established — do not trust unproven "food clash" claims.
Long heavy use can chill the spleen-stomach — bloating, belly pain, loose stools; sensitive people may get a rash or itching; overuse can also add to urination frequency. Stop and seek care at once for marked discomfort, an allergic reaction, persistent vomiting, trouble breathing, confusion, or a rapid worsening of symptoms.
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.
