Fruits and seedsAstringentSemen Myristicae

Rou Dou Kou (Nutmeg)

Q: What is Rou Dou Kou? Are Wei Rou Dou Kou, Bai Dou Kou, Cao Dou Kou and mace the same?

Official Rou Dou Kou (肉豆蔻) is the dried kernel of Myristica fragrans . The pharmacopoeial name is Myristicae Semen , also called Rou Guo or Yu Guo. Wei Rou Dou Kou is bran-roasted or flour-wrapped and roasted: part of the oil is driven off, slipping of the intestine and irritation are reduced, and astringing the intestine to stop diarrhea is stronger—this is the usual clinical form. Bai Dou Kou transforms damp, moves Qi and warms the middle to stop vomit; Cao Dou Kou dries damp, moves Qi and warms the middle to stop vomit—neither is nutmeg. Mace (the aril) is a separate spice and not an equal stand-in for the kernel. Writing Rou Dou Kou usually means the roasted piece; crush it at use. Raw powder in excess is toxic and must not be swallowed in kitchen-size handfuls.

Q: What are the TCM properties and traditional uses of Rou Dou Kou?

According to the Chinese Pharmacopoeia, Rou Dou Kou is acrid and warm , enters the Spleen, Stomach and Large Intestine channels, and acts to warm the middle and move Qi, and astringe the intestine to stop diarrhea . It is used for Spleen-Stomach deficient cold, incessant chronic diarrhea, epigastric-abdominal distending pain, and poor appetite with vomiting. Acrid-warm, aromatic and also astringent—suited to middle cold with Qi stagnation and deficient-cold lingering diarrhea, not to damp-heat dysentery or Yin-deficiency fire.

Q: What is the usual dosage? Can it be used daily as a spice to stop diarrhea?

The pharmacopoeial decoction dose is 3–10 g (commonly 3–9 g). It is not unlimited kitchen nutmeg powder. A few grams of raw powder can already cause dizziness and hallucination; large amounts can cause delirium and convulsions—never self-swallow large doses of powder. Deficient-cold lingering diarrhea needs a practitioner to name the roasted piece and a short course.

Q: How do you choose and store Rou Dou Kou?

Choose ovoid kernels, gray-brown with a netted surface, a marble-like cut face, a strong aroma and an acrid taste . Oily-dried, scentless, moldy and moth-eaten lots are inferior. Store cool and dry against moths; do not overheat the store or the aroma fades. Buy pharmacopoeial Rou Dou Kou or Wei Rou Dou Kou; do not replace a decoction dose with an equal weight of kitchen nutmeg powder, and never swallow a large raw amount.

A practical guide to Rou Dou Kou: 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 13, 2026

Quick Facts

Latin Name	Semen Myristicae
Chinese Name & Pinyin	肉豆蔻 · Rou Dou Kou
Medicinal Part	Fruits and seeds
The herb	Rou Dou Kou is the dried nutmeg kernel. Mace is a different part. Common form: roasted (wei). Kitchen powder is not the official piece.
Nature and channels	Acrid, warm. Enters the Spleen, Stomach, and Large Intestine. Acridity moves qi. Warmth clears middle cold. It also astringes the intestines.
Pharmacopoeia line	Warms the middle and moves qi. Astringes the intestines and stops diarrhea. Used for spleen-stomach deficiency-cold, lingering diarrhea, epigastric and abdominal distention and pain, poor appetite, and vomiting.
Pattern cues	Deficiency-cold lingering diarrhea. Dawn diarrhea. Cold abdominal pain. Poor appetite and vomiting. Pale tongue with white coating.
In this article	Roasted kernel versus kitchen powder and versus mace. How it differs from Bu Gu Zhi, He Zi, and Shi Liu Pi. Why damp-heat should not be astringed. Why a large raw dose is unsafe. Who should skip it.

What Is Rou Dou Kou?

Rou Dou Kou (肉豆蔻; Ròu Dòu Kòu; Latin: Myristicae Semen; English: nutmeg) is the dried kernel of Myristica fragrans Houtt. In Chinese medicine it is an astringent herb. It is acrid and warm, enters the Spleen, Stomach, and Large Intestine channels, and its core actions are to warm the middle and move qi, and to astringe the intestines and stop diarrhea. It is not kitchen nutmeg dusted freely on food. Culinary amounts are tiny. The official piece is processed and dosed in grams. It is not mace (the aril). Raw kernel is oily and harsh. Tradition usually uses roasted (wei) Rou Dou Kou to cut the oil and strengthen astringency. The seed contains volatile constituents. Large raw amounts are toxic. Do not grind a heavy home dose.

It is used most often for three patterns:

Deficiency-cold lingering diarrhea — dawn loose stools, undigested food
Cold abdominal pain with qi stagnation — pain that likes warmth, distention
Poor appetite and vomiting — cold weak spleen and stomach

After roasting, it is less acrid-dry and more astringent for diarrhea. The usual decoction dose is 3–9 g. Damp-heat diarrhea, excess-heat accumulation, and yin-deficiency fire are contraindications. Acrid-warm and intestine-astringing, it is not an unlimited dessert spice.

In spleen–kidney deficiency-cold and fifth-watch diarrhea, Rou Dou Kou warms and astringes. With Bu Gu Zhi, Wu Wei Zi, and Wu Zhu Yu it is Si Shen Wan. It warms and binds more than it clears. Foul yellow diarrhea with burning at the anus gets worse if more astringency is added.

Rou Dou Kou is not a catch-all antidiarrheal, and it is not a spice to taste in large amounts. In damp-heat diarrhea, or when there is no cold and no deficiency, using it alone can trap the pathogen. A large dose adds toxicity risk. Whether the roasted form belongs in a formula should be decided by a licensed Chinese medicine practitioner after pattern diagnosis.

Rou Dou Kou: Materia Medica Profile

Identification & Quality Standard

Semen Myristicae

Botanical Origin

The dried kernel of Myristica fragrans Houtt.(Myristicaceae).

Production Regions

Primarily produced in Malaysia, Indonesia, Sri Lanka, cultivated in the Chinese provinces of Guangdong, Guangxi, Yunnan.

Quality Requirements

Superior medicinal material is large, externally purplish-brown lustrous, with full and white kernel.

Macroscopic Features

Oval or elliptical shape, 2~3cm long, 1.5~2.5cm diameter. Externally grayish-brown or grayish-yellow, sometimes externally covered in white powder (lime powder). Whole body has pale longitudinal grooves and irregular grooves. Hilum is located in the wide end; pale round and raised, chalaza is dark and indented. Raphe is longitudinal groove connecting the two ends. Firm texture, fractured surface has a brownish-yellow alternating pattern, wide end has dry wrinkled embryo, oily. Potent aromatic odor, acrid taste.

Origin and Quality Identification

While it is primarily sourced from Southeast Asian countries like Indonesia and Malaysia, quality can vary based on harvest time, processing, and storage.

Appearance: High-quality Rou Dou Kou (Nutmeg) is oval-shaped, firm, and features a grayish-brown, net-like texture on the surface. When broken open, the inside is brownish.
Aroma and Taste: It has a rich, pungent fragrance—often described as a mix of camphor and cinnamon. The taste is distinctly spicy and slightly bitter.
Raw vs. Roasted: The raw herb has a smoother surface and a sharper scent. The roasted form (Wei Rou Dou Kou) often has bran residue on the outside, a gentler, slightly charred aroma, and a looser texture.

Traditional Properties & Historical Lineage

Nature, Flavour & Channel Tropism

Acrid, Bitter; WarmSpleenStomachLarge Intestine

1. Historical Records

Ming Yi Bie Lu: Noted its ability to warm the middle, aid digestion, and stop diarrhea. It was historically used for cold-induced abdominal pain and nausea.
Ben Cao Gang Mu: Highlighted its dual action to "warm the Spleen and Stomach" and "secure the Large Intestine," solidifying its role in digestive health.
De Pei Ben Cao: Focused on its use for chronic diarrhea and abdominal pain caused by "Deficiency and Cold."

2. Evolution of TCM Understanding

Throughout history, practitioners have highlighted different strengths of the herb. Some leaned on its Qi-moving properties for bloating and gas, while others focused on its astringent nature for chronic, watery diarrhea. However, modern TCM consensus emphasizes its specific use for "Cold" patterns. It should be used with extreme caution if the digestive issues are caused by "Heat" (e.g., acute bacterial infections with a burning sensation).

Core Efficacies & Traditional Applications

Traditional Functions

Warms the middle, astringes intestines, moves qi, resolves food. Apply to diarrhea of deficiency type, cold dysentery, gastric and abdominal swelling pain, poor appetite and vomiting, indigestion.

1. Primary Focus: Warming the Middle and Moving Qi

The traditional primary function of Rou Dou Kou (Nutmeg) is warming the Spleen and Stomach and unblocking stagnant Qi.

Target Symptoms: It is ideal for "Cold" and "Deficiency" patterns in the Spleen and Stomach. Symptoms include abdominal coldness, dull pain that worsens after eating cold foods, post-meal bloating, poor appetite, and even nausea or vomiting.
Common Pairings: To enhance its warming effect, it is often paired with Gan Jiang (Dried Ginger) or Wu Zhu Yu (Evodia Fruit). If bloating is severe, it is combined with Mu Xiang (Aucklandia Root) or Sha Ren (Amomum Fruit) to move Qi and relieve pain.
When to Avoid: Do not use this herb if you have a "Heat" body type (e.g., frequent mouth ulcers, dry stools, bad breath). Misusing its warming nature can worsen heat symptoms or aggravate stomach pain caused by spicy foods.

2. Secondary Focus: Astringing the Intestines and Stopping Diarrhea

Its second major function is to astringe (bind) the intestines to stop chronic diarrhea.

Target Symptoms: It is widely used for chronic, recurrent diarrhea caused by "Cold" and "Deficiency." Symptoms include watery stools with undigested food, cold hands and feet, worsening diarrhea after fatigue or exposure to cold, and a heavy sensation in the lower abdomen.
Common Pairings: It is usually paired with Qi-tonifying herbs like Dang Shen (Codonopsis Root) and Bai Zhu (Atractylodes Rhizome). For Kidney deficiency, it is combined with Bu Gu Zhi (Psoralea Fruit) and Wu Wei Zi (Schisandra Fruit) to secure the intestines.
When to Avoid: Never use for acute, "Heat-type" diarrhea (sudden onset, foul-smelling stools, burning sensation, or fever). Astringent herbs can trap the heat or bacterial infection inside. It is also unsuitable for diarrhea caused by food stagnation (sticky stools with severe bloating).

3. Common Herb Pairings

A classic combination is Rou Dou Kou (Nutmeg) with Mu Xiang (Aucklandia Root).

Synergy: Rou Dou Kou warms the digestive tract and stops diarrhea, while Mu Xiang moves Qi to stop pain and aids digestion. Together, they perfectly address abdominal bloating, pain, and intestinal rumbling caused by cold and stagnation.
Note: Both are warming herbs, so they must be used under professional guidance and avoided by those with internal heat.

Modern Research

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

1. Main Chemical Components

Modern analysis shows that Rou Dou Kou (Nutmeg) contains volatile oils (about 5% to 15%), fatty oils, and lignans.

In laboratory settings, these essential oils have shown the ability to regulate intestinal smooth muscle contractions.
Animal studies suggest the extracts can inhibit overactive bowel movements, which aligns with its traditional use for diarrhea. However, robust human clinical trials are still pending.

2. Modern Pharmacological Focus

Current scientific research is largely focused on isolating the volatile oils and exploring their potential to relieve intestinal spasms and suppress animal inflammatory responses. While the lab results are promising for gastrointestinal regulation, they remain foundational rather than clinically conclusive for human medicine.

3. Limitations of Modern Research

Animals Aren't Humans: In vitro and animal models have different metabolic pathways than humans; lab results cannot guarantee the same effects in everyday use.
Extracts vs. Whole Herbs: Modern lab extracts use highly concentrated active compounds. These behave entirely differently from a traditional water decoction of Rou Dou Kou (Nutmeg), meaning lab dosages do not apply to home brewing.
Methodology Gaps: Different studies use different extraction methods and plant varieties, leading to inconsistent data.
The Holistic Effect: TCM relies on the synergistic effect of the whole herb (and its combination with other herbs). Judging the entire plant's efficacy based on a single isolated chemical compound misses the broader picture of traditional medicine.

Comparing Similar Herbs

1. Shared Traits with Similar Herbs

Rou Dou Kou (Nutmeg) is often compared to Sha Ren (Amomum Fruit). Both are spicy, warming herbs that regulate the Spleen and Stomach. Both treat abdominal discomfort and poor appetite caused by cold or Qi stagnation, and both require caution in people with heat constitutions.

2. Core Differences

Nature and Flavor: While both are warm and spicy, Rou Dou Kou has a slightly bitter edge, giving it an astringent (binding) quality. Sha Ren is purely spicy and highly dispersing, with no binding effect.
Core Strengths: Rou Dou Kou excels at stopping chronic diarrhea and warming the lower digestive tract. Sha Ren is better at dissolving dampness, stimulating appetite, and calming the fetus during pregnancy.
Action Direction: Rou Dou Kou pushes energy downward and inward (astringing the bowels). Sha Ren pushes energy upward and outward (dispersing dampness in the upper/middle stomach).
Clinical Application: Rou Dou Kou is famously used in formulas for chronic cold diarrhea, such as Si Shen Wan (Four Miracle Pill). Sha Ren is preferred for acute indigestion or dampness, often seen in formulas like Xiang Sha Liu Jun Zi Tang (Six Gentlemen Decoction with Aucklandia and Amomum).

3. A One-Sentence Summary

Rou Dou Kou (Nutmeg) specializes in warming the lower gut to stop chronic diarrhea, while Sha Ren (Amomum Fruit) specializes in clearing dampness in the upper stomach to boost appetite and digestion.

Classical Formulas Containing Rou Dou Kou

Si Shen Wan

四神丸Minister

Formula CategoryAstringent FormulasPrimary PatternYang DeficiencyPrimary FunctionWarm Spleen-Kidney Yang, astringe intestines, stop diarrheaRelated ConditionsDiarrhea·Abdominal Pain·Poor Appetite·Cold Limbs

View Formula Profile Read Complete Guide

Formulas vs. Single Herbs

Synergy is Key: A formula is a balanced team. The healing power comes from how the herbs interact, so a single herb cannot simply replicate a full formula's effects.
Holistic Balance: The exact dosage and combination in a formula affect the entire body. Never try to mix or alter these formulas at home based on internet articles.

Diet & Daily Home Use

1. Home Herbal Teas and Soups

Nutmeg, Ginger, and Date Tea (For Mild Coldness):
- Ingredients: 3g Wei Rou Dou Kou (Roasted Nutmeg), 2 slices fresh ginger, 3 pitted red dates.
- Method: Crush the roasted nutmeg, slice the ginger, and tear the dates. Brew with boiling water in a thermos for 15 minutes.
- Best For: Mild intestinal rumbling, loose stools, or a chilled stomach during autumn and winter.
- Frequency: 1 to 2 times a week. Do not drink continuously. (Avoid if you have a heat constitution).
Nutmeg Pork Stomach Soup (For Chronic Weakness):
- Ingredients: 5g Wei Rou Dou Kou (Roasted Nutmeg), 1 pork stomach, 3 slices ginger, cooking wine.
- Method: Clean and blanch the pork stomach. Wrap the nutmeg in cheesecloth and place it inside the stomach. Simmer with water, ginger, and wine on low heat for 2 hours. Add salt to taste.
- Best For: Chronic poor appetite, mild abdominal pain, and loose stools due to Spleen coldness.

2. Processing Differences and Brewing

Raw vs. Roasted: Wei Rou Dou Kou (Roasted Nutmeg) has less volatile oil, making it milder, less irritating, and perfect for daily wellness. Sheng Rou Dou Kou (Raw Nutmeg) is much stronger and is mostly reserved for clinical prescriptions to treat severe stagnation.
Brewing: For home cooking, it does not require special boiling times; it can be stewed directly with food. For teas, simply crushing it is enough.

3. Dosage and Usage Cycle

Dosage: Clinical doses range from 3g to 10g. For home dietary use, stick to a very safe 3g to 5g.
Cycle: Use for short cycles of 3 to 5 days. Stop once symptoms improve. Long-term use requires a practitioner's guidance to prevent stomach irritation.

Contraindications & Safety Warnings

1. Who Should Avoid It

Heat Constitutions: People who run hot, have dry stools, bad breath, or easily get mouth ulcers.
Acute Diarrhea: Anyone with sudden, foul-smelling diarrhea accompanied by burning or fever.
Digestive Blockage: If you have severe bloating with foul-smelling gas and sticky stools, avoid this herb.
Vulnerable Populations: Pregnant and nursing women must exercise extreme caution, as safety data is limited. Children and the elderly should strictly follow a doctor's dosage. Those with liver or kidney impairment must consult a doctor, as the herb is metabolized through these organs.

2. Drug Interactions and Dietary Notes

Medications: Rou Dou Kou (Nutmeg) may interact with sedatives (increasing drowsiness), blood thinners (affecting metabolism and bleeding risk), and blood pressure/blood sugar medications. Always space out consumption and consult your doctor.
Dietary Combinations: While there are no strict "toxic" food pairings, always check with a pharmacist if you are taking prescription drugs before adding medicinal herbs to your diet.

3. Adverse Reactions and Overdose Risks

Side Effects: While safe at standard culinary and dietary doses, an overdose can cause nausea, vomiting, dizziness, and agitation. Severe overdose may lead to hallucinations or difficulty breathing (due to the compound myristicin).
When to Seek Help: If you experience any allergic reactions, persistent vomiting, mental confusion, or breathing issues, stop use immediately and seek emergency medical care.

Frequently Asked Questions About Rou Dou Kou

What is Rou Dou Kou? Are Wei Rou Dou Kou, Bai Dou Kou, Cao Dou Kou and mace the same?

Official Rou Dou Kou (肉豆蔻) is the dried kernel of Myristica fragrans. The pharmacopoeial name is Myristicae Semen, also called Rou Guo or Yu Guo. Wei Rou Dou Kou is bran-roasted or flour-wrapped and roasted: part of the oil is driven off, slipping of the intestine and irritation are reduced, and astringing the intestine to stop diarrhea is stronger—this is the usual clinical form. Bai Dou Kou transforms damp, moves Qi and warms the middle to stop vomit; Cao Dou Kou dries damp, moves Qi and warms the middle to stop vomit—neither is nutmeg. Mace (the aril) is a separate spice and not an equal stand-in for the kernel. Writing Rou Dou Kou usually means the roasted piece; crush it at use. Raw powder in excess is toxic and must not be swallowed in kitchen-size handfuls.

What are the TCM properties and traditional uses of Rou Dou Kou?

According to the Chinese Pharmacopoeia, Rou Dou Kou is acrid and warm, enters the Spleen, Stomach and Large Intestine channels, and acts to warm the middle and move Qi, and astringe the intestine to stop diarrhea. It is used for Spleen-Stomach deficient cold, incessant chronic diarrhea, epigastric-abdominal distending pain, and poor appetite with vomiting. Acrid-warm, aromatic and also astringent—suited to middle cold with Qi stagnation and deficient-cold lingering diarrhea, not to damp-heat dysentery or Yin-deficiency fire.

How do you choose raw versus roasted Rou Dou Kou? Should it be crushed?

Warm the middle to stop diarrhea and treat fifth-watch diarrhea with Wei Rou Dou Kou. The raw kernel is oily, slips the intestine and irritates, and is generally not used raw. It is hard: crush it at use before decoction. Do not boil it until the aroma is gone. Do not let it meet copper vessels.

What is the usual dosage? Can it be used daily as a spice to stop diarrhea?

The pharmacopoeial decoction dose is 3–10 g (commonly 3–9 g). It is not unlimited kitchen nutmeg powder. A few grams of raw powder can already cause dizziness and hallucination; large amounts can cause delirium and convulsions—never self-swallow large doses of powder. Deficient-cold lingering diarrhea needs a practitioner to name the roasted piece and a short course.

What are the contraindications? Can it be used in pregnancy?

Forbid in damp-heat diarrhea and dysentery and in Yin-deficiency fire; do not use an oversized dose. Intestinal wind with bleeding, Stomach-fire toothache and sudden damp-heat pouring are unsuitable. Use caution in pregnancy and in children; do not use raw powder. Stop at once and seek care if dizziness, palpitations or visual change appears. Do not abuse it as a “hallucinogenic spice.”

Can Rou Dou Kou stop diarrhea, warm the middle and move Qi to stop pain?

It can help deficient-cold patterns. Spleen-Kidney Yang deficiency fifth-watch diarrhea joins Psoralea, Evodia and Schisandra in Si Shen Wan. Middle-cold epigastric distention joins dried ginger, Aucklandia and ginseng. It warms and astringes together—not a specific for every diarrhea, every bloating or every dysentery. Acute bacillary dysentery and high fever with bloody stool are emergencies.

Can Rou Dou Kou be eaten daily as a baking spice, sleep or appetite powder?

A pinch in cooking is not the same dose as pharmacopoeial roasted nutmeg. Deficient-cold lingering diarrhea may enter a short formula; damp-heat and Yin deficiency only grow drier and more stagnant. “Nutmeg aids sleep and opens the appetite” does not replace gastroenterology, and raw powder must not be used for stimulation. Warming the middle and astringing the intestine should name Wei Rou Dou Kou and a 3–10 g dose.

How do you choose among Rou Dou Kou, Bai Dou Kou, Cao Dou Kou, Bu Gu Zhi and He Zi?

Nutmeg is acrid-warm: warms the middle, moves Qi and astringes the intestine to stop diarrhea—suited to deficient-cold lingering diarrhea with epigastric distention. White cardamom is acrid-warm: transforms damp, moves Qi and warms the middle to stop vomit—leaning to damp obstructing Qi with nausea. Tsaoko-type Alpinia is acrid-warm: dries damp, moves Qi and warms the middle to stop vomit—more drying. Psoralea is acrid-bitter-warm: supplements Kidney Yang, secures essence, reduces urination and warms the Spleen to stop diarrhea—leaning to Kidney-Yang fifth-watch diarrhea. Chebula is bitter-sour-astringent-neutral: astringes the intestine to stop diarrhea and constrains the Lung to downbear Qi—pure astringency. Fifth-watch diarrhea favors Rou Dou Kou and Bu Gu Zhi; damp obstruction with nausea favors Bai Dou Kou and Cao Dou Kou; slippage lingering diarrhea favors He Zi. They may be paired; all are wrong as pure warm astringency in damp-heat sudden diarrhea, and raw nutmeg powder must not be oversized.

Which herbs is Rou Dou Kou combined with? What are the representative formulas?

Spleen-Kidney deficient-cold fifth-watch diarrhea joins Psoralea, Evodia and Schisandra in Si Shen Wan. Middle-cold lingering diarrhea joins dried ginger, ginseng, Aucklandia and clove. Write Wei Rou Dou Kou, crush it into the decoction, and do not dispense Bai Dou Kou or raw powder.

How do you choose and store Rou Dou Kou?

Choose ovoid kernels, gray-brown with a netted surface, a marble-like cut face, a strong aroma and an acrid taste. Oily-dried, scentless, moldy and moth-eaten lots are inferior. Store cool and dry against moths; do not overheat the store or the aroma fades. Buy pharmacopoeial Rou Dou Kou or Wei Rou Dou Kou; do not replace a decoction dose with an equal weight of kitchen nutmeg powder, and never swallow a large raw amount.

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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.