Herb

Mang Xiao

Mirabilite | 芒硝

Also known as:

Mirabilite

Mang Xiao

Product appearance may vary from images shown

Properties

Purgatives (攻下药) · Cold

Traditionally supports*

Constipation Relief Digestive Health Detoxification Swelling and Inflammation

Parts Used

Mineral (矿物 kuàng wù)

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Select Product Type

Select Supplier

Select Size

Quantity

$21.00 ($0.21/g)
For shipments to: United States Change
Standard Shipping (3-5 business days): $4.99
Express Shipping (1-2 business days): $9.99
Free shipping on orders over $75

About This Herb

Traditional Chinese Medicine background and properties

Herb Description

Máng Xiāo is a mineral salt (sodium sulfate) used as a powerful natural laxative in Chinese medicine. It works by drawing water into the intestines to soften hard, dry stools and flush out excess Heat. It is also applied externally to reduce swelling and pain from conditions like sore throats, mouth ulcers, and breast engorgement.

Herb Category

Purgatives (攻下药)

Main Actions

  • Purges Heat and Unblocks the Bowels
  • Softens Hardness and Moistens Dryness
  • Clears Heat and Reduces Swelling

How These Actions Work

'Purges Heat and unblocks the bowels' means that Máng Xiāo draws water into the intestines through an osmotic effect, producing a strong laxative action that flushes out accumulated Heat and stagnant matter. This is its primary function and the reason it is used for severe constipation caused by excess Heat drying out the stool. It is almost always combined with Dà Huáng (rhubarb), and the two together form one of the most powerful purgative partnerships in Chinese medicine.

'Moistens Dryness and softens hardness' refers to Máng Xiāo's salty taste, which in TCM theory has the ability to soften things that have become hard and dry. In practical terms, it softens dry, compacted stool that has become rock-hard and immovable in the intestines. The salty flavour also has a natural downward-moving tendency, which aids elimination.

'Clears Fire and reduces swelling' describes Máng Xiāo's use both internally and externally for hot, swollen, painful conditions. Applied topically dissolved in water, it can reduce the swelling and pain of skin abscesses, inflamed hemorrhoids, sore throat, mouth ulcers, and red swollen eyes. It is also applied externally to the breasts to help with engorgement or weaning (stopping breastmilk production).

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony that reveal what's out of balance in the body. Mang Xiao is traditionally associated with these specific patterns.

The following describes this herb's classification within Traditional Chinese Medicine theory and is provided for educational purposes only.

Why Mang Xiao addresses this pattern

Máng Xiāo directly addresses the core pathomechanism of the Yángmíng Organ pattern: excess Heat that has dried the intestinal contents into hard, immovable stool. Its cold temperature clears the intense internal Heat, its salty taste softens the hardened fecal matter ('softens hardness'), and its osmotic effect draws water into the intestines to flush everything downward. It enters the Stomach and Large Intestine channels, which are exactly the organs affected in this pattern. This is the single most important pattern for Máng Xiāo and the reason it appears in the famous Chéng Qì Tāng family of formulas.

A practitioner would look for one or more of these signs

Constipation

Severe constipation with hard, dry stool that will not move

Abdominal Pain

Abdominal fullness and pain that worsens with pressure

Fever

Tidal fever, especially worsening in the afternoon

Delirium

Delirium or confused speech from intense internal Heat

TCM Properties

Temperature

Cold

Taste

Bitter (苦 kǔ), Salty (咸 xián)

Channels Entered
Stomach Large Intestine
Parts Used

Mineral (矿物 kuàng wù)

This is partial information on the herb's TCM properties. More detailed information is available on the herb's dedicated page

Product Details

Manufacturing, supplier, and product specifications

Product Type

Granules

Quantity Description

Loading quantity information...

Concentration Ratio

Loading concentration information...

Fabrication Method

Loading fabrication information...

Supplier Certifications

Loading certifications information...

Botanical & Sourcing

Quality Indicators

High-quality Mang Xiao should be in the form of clear, colorless or white, transparent prismatic crystals with a vitreous (glass-like) luster. The crystals should be clean, free of visible impurities or discoloration. The taste is distinctly salty and slightly bitter. Avoid product that appears dull, opaque, or has turned to white powder (indicating it has lost its crystallization water through weathering into thenardite/feng hua xiao). The best grade has large, well-formed, translucent crystals. Must be stored in sealed containers below 30°C to maintain quality.

Primary Growing Regions

Mang Xiao (mirabilite) is a mineral, not a cultivated plant, so it is collected rather than grown. It is widely distributed across China, found in provinces including Inner Mongolia, Hebei, Shanxi, Shandong, Jiangsu, Anhui, Henan, Hubei, Sichuan, Yunnan, Guizhou, Qinghai, Xinjiang, and Shaanxi. It forms naturally in arid regions around salt lakes and saline springs. Historically, high-quality sources were noted from Yizhou (益州, roughly modern Sichuan) and the Longxi (陇西) region. In modern times, the best refined Mang Xiao comes from Sichuan and Hubei provinces, where traditional processing methods are well established.

Harvesting Season

Year-round (全年均可采制). As a mineral, it can be collected in any season, though traditionally harvested from salt lake deposits during dry periods when crystallization is most abundant.

Supplier Information

Treasure of the East

Loading supplier information...

Loading supplier attributes...

Miscellaneous Info

No additional information available

Usage & Safety

How to use this herb and important safety information

Important Medical Disclaimer

The information provided here is for educational purposes only and is not intended as medical advice or to replace consultation with a qualified healthcare professional. This herb is a dietary supplement and has not been evaluated by the FDA. It is not intended to diagnose, treat, cure, or prevent any disease.

Always consult with a qualified healthcare provider, particularly if you are pregnant, nursing, have a medical condition, or are taking other medications. Discontinue use and consult your healthcare provider if you experience any adverse reactions.

Recommended Dosage

Loading dosage information...

Instructions for safe storage and consumption

Loading storage and consumption information...

Traditional Dosage Reference

Standard

6–12g

Maximum

Up to 15g for severe dry constipation with Heat binding, under practitioner supervision. Higher doses risk excessive fluid loss and electrolyte disturbance.

Notes

Mang Xiao is typically used at 6–12g for internal purposes. Lower doses (6–9g) provide a gentle moistening laxative effect, while higher doses (10–15g) are used for severe Heat-binding constipation with hard, dry stools. When combined with Da Huang (rhubarb) in formulas like Da Cheng Qi Tang, the synergistic effect is powerful and dosage may be kept moderate. For external use (mastitis, skin sores, hemorrhoids), an appropriate amount is dissolved in water and applied topically. Xuan Ming Fen (the weathered, anhydrous form) is milder and is preferred when a gentler action is desired, particularly for patients who are slightly weakened.

Processing Methods

Processing method

Máng Xiāo crystals are placed in a flat-bottomed basin or wrapped in paper and hung in a well-ventilated, dry area to allow natural weathering (风化). The crystalline water gradually evaporates, leaving behind a fine white anhydrous powder (Na₂SO₄). The temperature must remain below 32°C during this process; otherwise the crystals liquefy instead of forming powder. An alternative method heats the crystals gently in a porcelain basin over a water bath until all moisture has evaporated.

How it changes properties

The temperature remains cold and the taste remains salty-bitter, but the purgative (laxative) action becomes significantly milder. The mineral is now purer anhydrous sodium sulfate. Because the osmotic laxative effect depends partly on the hydrated form, the dehydrated Xuán Míng Fěn is less effective as a purgative but retains strong Heat-clearing and swelling-reducing properties. It becomes particularly suited for topical use on mucous membranes.

When to use this form

Preferred for topical applications: mouth ulcers, throat inflammation, red swollen eyes, and skin conditions. Also used internally when a milder purgative effect is desired, or in patients who need Heat-clearing without drastic purging. It is the form used in formulas like Bīng Péng Sǎn for throat and mouth conditions.

Toxicity Classification

Non-toxic

Mang Xiao (refined sodium sulfate decahydrate) is classified as non-toxic in the Chinese Pharmacopoeia. It is essentially a purified mineral salt. However, excessive dosage acts as a powerful osmotic laxative, drawing large amounts of water into the intestines. This can cause severe diarrhea, dehydration, and electrolyte imbalance (particularly sodium and potassium disturbances). Prolonged or excessive use may damage Spleen Yang and deplete body fluids. In healthy adults at standard dosage (6-12g), no toxic effects are expected. The traditional processing method of recrystallizing crude Pu Xiao with radish (luobo) removes impurities such as excess magnesium and calcium sulfates, producing a purer and safer product. Must be stored sealed below 30°C to prevent dehydration into thenardite powder (feng hua xiao / 风化硝).

Contraindications

Avoid

Pregnancy: Mang Xiao has purgative and downward-draining properties that can stimulate uterine contractions and potentially cause miscarriage. Classical texts explicitly prohibit its use during pregnancy.

Avoid

Spleen and Stomach deficiency cold (pi wei xu han): Mang Xiao is drastically cold in nature. Using it in someone whose digestive system is already weak and cold will severely damage the Spleen Yang, worsening diarrhea, poor appetite, and abdominal pain.

Avoid

Absence of interior excess heat or dry stool: Mang Xiao is only indicated when there is genuine Heat binding with dry, hard stool. If the constipation is due to Qi deficiency, Blood deficiency, or cold, this herb will cause harm without benefit.

Caution

Active menstruation or postpartum bleeding: The herb's strong purgative and Blood-moving properties may exacerbate bleeding.

Caution

Elderly or constitutionally weak patients: The powerful draining action can deplete Qi and fluids. If use is essential, the dose should be carefully reduced and combined with tonifying herbs.

Avoid

Gastrointestinal obstruction or perforation: The osmotic laxative action could worsen an existing bowel obstruction or perforation.

Caution

Severe dehydration or electrolyte imbalance: As an osmotic purgative (sodium sulfate), Mang Xiao draws water into the intestines and can worsen fluid and electrolyte depletion.

Caution

Impaired kidney function: Sodium sulfate can place additional burden on the kidneys. Use with caution and ensure adequate hydration.

Classical Incompatibilities

Mang Xiao appears twice in the Nineteen Mutual Fears (十九畏): 1. Liu Huang (硫黄, Sulfur) fears Pu Xiao/Mang Xiao (硫黄畏朴硝) 2. Ya Xiao/Mang Xiao fears San Leng (牙硝畏三棱, Sparganium) Additionally, the classical note from Ben Cao Jing Ji Zhu states: "Shi Wei (石韦, Pyrrosia leaf) serves as its envoy (使). It fears Mai Ju Jiang (麦句姜)."

Special Populations

Pregnancy

Contraindicated. Classical texts including the Pin Hui Jing Yao (《品汇精要》) explicitly state that Mang Xiao must not be used during pregnancy (妊娠不可服). As a powerful osmotic purgative, it strongly stimulates intestinal peristalsis and can induce uterine contractions. The Ben Cao Jing notes it can cause miscarriage (堕胎). While the Shang Han Lun tradition allows cautious use in life-threatening situations during pregnancy under the principle of "you gu wu yun" (有故无殒, when there is a clear pathological cause, treating it will not harm the fetus), this requires expert clinical judgment and is not a standard recommendation.

Breastfeeding

Use with caution. Mang Xiao's active component (sodium sulfate) can pass into breast milk and may cause loose stools or diarrhea in the nursing infant. Interestingly, when applied externally to the breasts, Mang Xiao (usually as Pi Xiao, the crude form) is a traditional method for promoting milk return (cessation of lactation) or treating early-stage mastitis (breast abscess), and has been clinically documented for this use. If internal use during breastfeeding is clinically necessary, the lowest effective dose should be used for the shortest possible duration, and the infant should be monitored for loose stools.

Pediatric Use

Can be used in children for genuine excess Heat constipation, but the dose must be significantly reduced according to age and weight, typically one-quarter to one-half of the adult dose. Very young children and infants have immature digestive systems that are more sensitive to osmotic purgatives, so use is generally not recommended for children under 3 years. For childhood digestive accumulation (shi ji, 食积), crude Pi Xiao applied externally to the abdomen is a safer traditional method than internal use. Close monitoring for dehydration is essential in any pediatric application.

Drug Interactions

Reduced absorption of oral medications: As an osmotic laxative, Mang Xiao accelerates intestinal transit and can reduce the absorption of concurrently administered oral medications. Oral drugs should ideally be taken at least 1–2 hours before Mang Xiao to ensure adequate absorption. This is particularly important for medications with narrow therapeutic windows such as digoxin, warfarin, oral contraceptives, and anti-epileptics.

Diuretics and nephrotoxic drugs: Because Mang Xiao causes fluid shifts into the intestine, concurrent use with diuretics (furosemide, hydrochlorothiazide), ACE inhibitors, ARBs, or NSAIDs may increase the risk of dehydration, electrolyte imbalance, and renal impairment.

Cardiac glycosides (digoxin): Electrolyte disturbance from osmotic purging (particularly hypokalemia and hypomagnesemia) can increase sensitivity to digoxin toxicity.

Antihypertensive medications: The fluid and electrolyte shifts caused by Mang Xiao may cause unpredictable drops in blood pressure when combined with antihypertensives.

Tetracycline and fluoroquinolone antibiotics: Sodium sulfate preparations can reduce the absorption of these antibiotics.

Dietary Advice

While taking Mang Xiao, avoid cold, raw, and greasy foods that further burden the digestive system. Drink adequate warm fluids to replenish the water drawn into the intestines by the herb's osmotic action. Avoid excessively salty foods, as Mang Xiao is itself a sodium salt. Light, easily digestible foods such as rice congee are recommended during and after use. Avoid alcohol, as it can worsen dehydration.

Cautions & Warnings

Although this formula is typically safe for most individuals, it may cause side effects in some people. Pregnant women, nursing mothers, postpartum women, and those with liver disease should use the formula with caution.

As with any Chinese herbal remedy, it is advisable to seek guidance from a qualified TCM practitioner before beginning treatment.