Rou Dou Kou

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Myristica fragrans Houtt.

Genus: Myristica Species: fragrans Pinyin: Rou Dou Kou
Nutmeg肉豆蔻

☯ TCM Properties

Category: astringent
Temperature: warm
Taste: pungent
Meridians: spleen, stomach, large intestine
Functions:

Regulates Qi and Harmonizes the Middle Burner; Astringes the Intestines and Stops Diarrhea; Warms the Interior and Dispels Cold; Promotes Digestion and Resolves Food Stagnation

Traditional Chinese Uses

Rou Dou Kou (nutmeg seed) is a pungent, warm, astringent herb used to warm the Spleen and Stomach, bind the intestines, and move Qi to relieve pain and fullness. It is particularly effective for chronic, cold-type diarrhea occurring in the early morning hours — the pattern called "cockcrow diarrhea" associated with Kidney and Spleen Yang deficiency. It is often combined with other warming and astringent herbs for this purpose.

Western Herbalism Properties

Actions:
carminativestimulantastringent

Botanical Description

Myristica fragrans Houtt. (Myristicaceae) is a dioecious, evergreen tropical tree native to the Banda Islands of Indonesia and now cultivated throughout the moist tropics. It reaches 5 to 20 meters in height with a spreading, conical crown and dark, smooth bark exuding a watery red sap when cut. The leaves are alternate, elliptic to oblong-lanceolate, 5 to 15 cm long, dark green and glossy above and paler below, with entire margins and a leathery texture. The small, pale yellow, fleshy, bell-shaped flowers are borne in axillary umbel-like cymes, the staminate and pistillate flowers usually on separate trees. The fruit is a fleshy, yellow, pear-shaped to globose drupe-like capsule 5 to 8 cm long that splits open at maturity into two valves, revealing a single ovoid seed covered by a brilliant red, lacy aril. The hard, brown, oval seed kernel constitutes nutmeg, used as Rou Dou Kou in Chinese medicine, while the dried aril is the spice mace.

Active Constituents

Myristicin

Phenylpropanoid (methylenedioxy phenylpropene)

Concentration: Major essential-oil component

A principal aromatic constituent; a weak monoamine-oxidase inhibitor that is metabolized toward amphetamine-type derivatives (e.g., MMDA), responsible for nutmeg's psychoactive and toxic effects at high doses, and studied for neuroprotective and chemopreventive activity.

Macelignan

Lignan

Concentration: Bioactive seed lignan

A well-studied lignan with anti-inflammatory, antimicrobial and antioxidant activity in experimental models.

Eugenol

Phenylpropanoid

Concentration: Essential-oil component

Contributes antimicrobial, analgesic and antioxidant activity and part of the warming, aromatic character of the seed.

Sabinene and terpinen-4-ol

Monoterpenes

Concentration: Among the most abundant essential-oil constituents

Major monoterpenes of nutmeg oil associated with antimicrobial and anti-inflammatory activity.

Elemicin and safrole

Phenylpropanoids

Concentration: Minor essential-oil components

Aromatic ethers that, alongside myristicin, contribute to the psychoactive and potentially toxic profile of high-dose nutmeg.

Malabaricone C

Diarylnonanoid

Concentration: Minor phenolic constituent

Shows strong antioxidant, antimicrobial and neuroprotective/chemopreventive activity in laboratory studies.

meso-Dihydroguaiaretic acid

Lignan

Concentration: Minor lignan

A lignan with anti-inflammatory and antimicrobial activity contributing to the seed's pharmacology.

Trimyristin (fixed oil)

Triacylglycerol / fixed oil

Concentration: Large fraction of the seed (nutmeg butter)

The solid fixed oil (nutmeg butter) rich in myristic acid; the carrier of the astringent, warming preparation used to bind the intestines.

⚠ Drug Interactions

Monoamine-oxidase inhibitors (MAOIs) and serotonergic drugs (SSRIs)

Moderate Evidence: Theoretical

Myristicin is a weak MAO inhibitor and several nutmeg constituents are structurally related to monoamine neurotransmitters. In large (toxic) doses this could add to the effects of MAOIs and serotonergic agents, theoretically increasing risk of hypertensive or serotonergic reactions.

Clinical note: At normal culinary/medicinal doses (3-9 g processed) the risk is low; avoid large nutmeg doses in patients on MAOIs or serotonergic antidepressants.

Anticholinergic and CNS-active / psychotropic drugs

Moderate Evidence: Theoretical

High-dose nutmeg produces anticholinergic-like and CNS effects (delirium, tachycardia, flushing) documented in poisoning case reports. Combining toxic doses with anticholinergic or centrally acting drugs could compound these effects.

Clinical note: Relevant only to overdose; observe the standard low medicinal dose and avoid combining large amounts with sedatives or anticholinergics.

Dosage

FormAmount Frequency Duration Population Notes
decoction 6-15g Daily

Preparation Methods

Roasted / bran-processed decoction (Wei Rou Dou Kou)

Parts: Seed kernel

To astringe the intestines and stop chronic diarrhea, the seed is roasted or wrapped in flour/bran paste and dry-heated (wei) to drive off part of the volatile oil before use, then decocted, typically 3-9 g. Processing reduces the irritant and psychoactive oil while preserving the astringent, warming action.

Powder

Parts: Seed kernel

The processed seed may be ground to a fine powder and taken in small divided doses (about 1.5-3 g) for daybreak (cock-crow) diarrhea and cold-type digestive weakness. WARNING: do NOT exceed medicinal dose; single large amounts (about 5 g or more of raw ground nutmeg) can cause psychoactive and toxic reactions from myristicin.

Clinical Studies

Nutmeg (Myristica fragrans Houtt.) essential oil: A review on its composition, biological, and pharmacological activities

Ashokkumar K, Simal-Gandara J, Murugan M, Dhanya MK, Pandian A (2022) Phytotherapy Research Review

Reviews the composition of nutmeg essential oil (monoterpenes such as sabinene and terpinen-4-ol; phenylpropenes eugenol, methyleugenol and myristicin) and its antimicrobial, antiseptic, antiparasitic, anti-inflammatory and antioxidant activities.

Chemical diversity and pharmacological significance of the secondary metabolites of nutmeg (Myristica fragrans Houtt.)

Abourashed EA, El-Alfy AT (2016) Phytochemistry Reviews Review

Catalogs the phenylpropanoids, lignans (macelignan, dihydroguaiaretic acid), diarylnonanoids (malabaricone C) and terpenoids of nutmeg and their reported neuroprotective, gastrointestinal, hypoglycemic and antioxidant activities.

Historical Texts

Yao Xing Lun (Treatise on the Nature of Medicinals)

Sui-Tang, c. 7th century CE
Early record of Rou Dou Kou for warming the middle, moving Qi and checking diarrhea.

Kai Bao Ben Cao (Materia Medica of the Kaibao Era)

Northern Song dynasty, 973-974 CE
Formally lists Rou Dou Kou (imported nutmeg) and its warming, astringent digestive uses.

Ben Cao Gang Mu (Compendium of Materia Medica), Li Shizhen

Ming dynasty, 1596
Describes processing to reduce the oil and use to warm the Spleen/Stomach and bind the intestines against chronic diarrhea.

References

  1. Ashokkumar K, Simal-Gandara J, Murugan M, Dhanya MK, Pandian A. Nutmeg (Myristica fragrans Houtt.) essential oil: A review on its composition, biological, and pharmacological activities . Phytotherapy Research (2022) [DOI]
  2. Abourashed EA, El-Alfy AT. Chemical diversity and pharmacological significance of the secondary metabolites of nutmeg (Myristica fragrans Houtt.) . Phytochemistry Reviews (2016) [DOI]

This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.

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