Herb Whole plant / Aerial parts (全草 quán cǎo)

Bo He

Peppermint herb · 薄荷

Mentha haplocalyx Briq. · Herba Menthae Haplocalycis

Also known as: Mint Herb

Bo He (Peppermint herb) plant

Images shown are for educational purposes only

Bo He (mint herb) is a light, aromatic, cooling herb widely used in Chinese medicine for colds with sore throat and fever, headaches, red eyes, and skin rashes. It also gently soothes emotional tension and helps relieve stress-related chest tightness by promoting the smooth flow of Liver Qi. It is found in many well-known formulas and is also popular as a food and tea ingredient.

Category Cool, acrid herbs that release the Exterior (辛凉解表药)
Therapeutic focus Cold and Flu Relief Headache Relief Throat Health Stress and Anxiety Skin Health

TCM Properties

Temperature

Cool

Taste

Acrid / Pungent (辛 xīn), Aromatic (芳香 fāng xiāng)

Channels entered

Lungs, Liver

Parts used

Whole plant / Aerial parts (全草 quán cǎo)

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Educational content • Consult qualified TCM practitioners for diagnosis and treatment

What This Herb Does

Every herb has a specific set of actions — here's what Bo He does in the body, explained in both everyday and TCM terms

Therapeutic focus

In practical terms, Bo He is primarily used to support these areas of health:

Cold and Flu Relief Headache Relief Throat Health Stress and Anxiety Skin Health

TCM Actions

In TCM terminology, these are the specific therapeutic actions that Bo He performs to restore balance in the body:

Disperses Wind-Heat Clears the Head and Brightens the Eyes Benefits the Throat Vents Rashes Courses the Liver and Resolves Constraint

How these actions work

'Disperses Wind-Heat' means Bo He drives out the early stages of a Wind-Heat invasion, the type of common cold that comes with fever, sore throat, and a headache rather than chills and runny nose. Its acrid, cool, aromatic nature opens the pores and promotes a light sweat, pushing the pathogen out through the body's surface. It is considered one of the most important herbs for this purpose and often appears in formulas for the initial stage of warm-febrile diseases (温病 wēn bìng).

'Clears the head and eyes' means Bo He is especially effective at relieving symptoms in the upper part of the body caused by Wind-Heat rising upward, such as headaches, red and painful eyes, and dizziness. Its light, ascending quality carries its cooling action directly to the head. This is why it frequently appears in formulas for headaches of various types.

'Benefits the throat' means Bo He reduces swelling and pain in the throat caused by Heat. It is commonly used for sore throat, hoarse voice, and mouth sores. Its cooling, aromatic nature soothes the inflamed tissues of the throat and mouth.

'Vents rashes' means Bo He helps measles or other rashes come to the surface when they are stuck and not erupting fully. In TCM, pushing a rash outward is considered a way to help the body expel a pathogen. Bo He's dispersing quality helps the rash emerge so the disease can resolve.

'Courses the Liver and resolves constraint' means Bo He can smooth the flow of Liver Qi when it becomes stagnant, which often shows up as emotional tension, chest tightness, rib-side pain, or menstrual irregularity. Because Bo He enters the Liver channel, even a small amount can help relieve the feeling of being 'stuck' emotionally or physically. This is why it appears in the famous formula Xiao Yao San (Free and Easy Wanderer).

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony. Bo He is used to help correct these specific patterns.

Why Bo He addresses this pattern

Bo He is one of the primary herbs for treating Wind-Heat invading the exterior. Its acrid taste disperses the pathogen outward, while its cool nature directly counteracts the Heat component of this pattern. Being aromatic and light, it rises to the head and upper body where Wind-Heat symptoms concentrate. It enters the Lung channel, which governs the body's surface defence (Wei Qi), making it ideally positioned to expel exterior Wind-Heat at the onset of illness.

A practitioner would look for one or more of these signs

Fever

Fever with mild chills

Headaches

Headache from Wind-Heat

Sore Throat

Sore, red, swollen throat

Red Eyes

Red, painful eyes

Hypochondrial Pain That Is Worse On Coughing And Breathing

Cough with yellow phlegm

Commonly Used For

These are conditions where Bo He is frequently used — but only when they arise from the specific patterns it addresses, not in all cases

Arises from: Wind-Heat

TCM Interpretation

TCM distinguishes between Wind-Cold colds (chills predominate, clear runny nose, no sore throat) and Wind-Heat colds (fever predominates, sore throat, yellow nasal discharge). Bo He is specifically for the Wind-Heat type, where an external Heat pathogen has invaded the body's surface (the Wei or defensive level). The Lung channel, which governs the skin and breathing, is the first line affected. The pathogen lodges at the surface, blocking the pores and disrupting normal Lung function, producing fever, headache, sore throat, and cough.

Why Bo He Helps

Bo He's acrid taste opens the pores and disperses the pathogen outward, while its cool temperature directly opposes the Heat of the invading Wind. It enters the Lung channel, which governs the body's surface, making it ideally placed to expel external pathogens. Its aromatic quality also clears the nasal passages and soothes the throat. It is the lead herb in formulas like Yin Qiao San specifically because it combines strong dispersing power with cooling action, addressing both the Wind and Heat components of the cold simultaneously.

Also commonly used for

Influenza

Early-stage flu with fever and body aches

Sore Throat

Acute pharyngitis and tonsillitis

Viral Conjunctivitis

Red, swollen, painful eyes from Wind-Heat

Urticaria

Wind-Heat type hives and itching

Measles

Incomplete eruption of rash in early measles

Irritable Bowel Syndrome

When related to Liver Qi invading the Spleen

Mouth Ulcers

Oral ulcers from Wind-Heat or Liver Fire

Depression

Mild depressive states related to Liver Qi constraint

Herb Properties

Every herb has an inherent temperature, taste, and affinity for specific channels — these properties determine how it interacts with the body

Temperature

Cool

Taste

Acrid / Pungent (辛 xīn), Aromatic (芳香 fāng xiāng)

Channels Entered

Lungs Liver

Parts Used

Whole plant / Aerial parts (全草 quán cǎo)

Dosage & Preparation

These are general dosage guidelines for Bo He — always follow your practitioner's recommendation, as dosages vary based on the formula and your individual condition

Standard dosage

3-6g

Maximum dosage

Up to 10g in acute Wind-Heat conditions requiring strong dispersal, for short-term use only. Higher doses increase the risk of excessive sweating and fluid depletion.

Dosage notes

Use lower doses (3g) when Bo He serves as an assistant herb for Liver-soothing or mild head-clearing purposes, as in Xiao Yao San. Use the standard range (3-6g) for dispersing Wind-Heat in acute colds. Bo He leaf (Bo He Ye) is stronger for sweating and exterior-releasing, while Bo He stem (Bo He Geng) is milder and better for moving Qi and harmonizing the middle. Because it is aromatic and volatile, Bo He should not be decocted for extended periods or its active components will be lost.

Preparation

Bo He must be added to the decoction near the end of cooking (hou xia, 后下), typically in the last 3-5 minutes only. Its therapeutic value comes from volatile aromatic oils (mainly menthol) that are easily lost with prolonged boiling. Extended decoction destroys the active components and renders the herb ineffective.

Processing Methods

In TCM, the same herb can be prepared in different ways to change its effects — here's how processing alters what Bo He does

Processing method

Dry-fried in a wok over medium heat until the colour darkens slightly and the aroma becomes less volatile.

How it changes properties

Dry-frying moderates Bo He's dispersing and diaphoretic nature, reducing its sweat-promoting effect. The temperature remains cool but the ascending, scattering force is gentler.

When to use this form

When the patient already has sweating and you want Bo He's Liver-coursing or head-clearing effects without promoting further sweat loss.

Common Herb Pairs

These ingredients are traditionally combined with Bo He for enhanced therapeutic effect

Ju Hua
Ju Hua 1:1 (Bo He 6g : Ju Hua 6g)

Both Bo He and Ju Hua disperse Wind-Heat and clear the head and eyes. Bo He is stronger at dispersing and promoting sweat, while Ju Hua excels at calming the Liver and clearing Liver Fire. Together they powerfully clear Wind-Heat from the head, treating headaches, red eyes, and dizziness more effectively than either alone.

When to use: Wind-Heat headache with red, painful eyes and dizziness, or Liver Fire rising to the head.

Niu Bang Zi
Niu Bang Zi 1:1 (Bo He 6g : Niu Bang Zi 6g)

Both herbs disperse Wind-Heat, benefit the throat, and vent rashes. Niu Bang Zi is stronger at clearing Heat-toxin and resolving swelling, while Bo He has stronger dispersing and diaphoretic action. Used together, they mutually enhance each other's ability to clear the throat and push out rashes.

When to use: Wind-Heat sore throat, early-stage measles with incomplete rash eruption, or mumps with swelling.

Chai Hu
Chai Hu Chai Hu 6-9g : Bo He 3-6g

Chai Hu rises and disperses to resolve Liver constraint, while Bo He provides cool, aromatic relief that vents stagnant Liver Qi and clears the resulting Heat. Together they form a powerful Liver-soothing pair that is stronger than either herb alone at restoring the Liver's free-flowing nature.

When to use: Liver Qi stagnation with rib-side pain, chest oppression, emotional irritability, or menstrual irregularity. This pair forms the core dispersing mechanism in Xiao Yao San.

Jing Jie
Jing Jie 1:1 (Bo He 6g : Jing Jie 6g)

Jing Jie is warm and acrid, dispersing Wind-Cold, while Bo He is cool and acrid, dispersing Wind-Heat. Paired together, they cover both Wind-Cold and Wind-Heat patterns and are especially effective at venting rashes and relieving skin itching. The combination is broader in scope than either herb alone.

When to use: Skin conditions with itching (urticaria, eczema), incomplete measles eruption, or early-stage colds where the Wind type is unclear.

Jie Geng
Jie Geng Bo He 6g : Jie Geng 6g

Bo He disperses Wind-Heat and clears the throat from above, while Jie Geng opens the Lung Qi and pushes upward to benefit the throat from below. Together they effectively clear heat and inflammation from the throat, making this a classic pairing for sore throat management.

When to use: Acute sore throat and pharyngitis from Wind-Heat, hoarse voice, and throat swelling.

Key Formulas

These well-known formulas feature Bo He in a prominent role

Chuan Xiong Cha Tiao San 川芎茶调散 King

In Chuan Xiong Cha Tiao San, Bo He is used in the largest dosage (8 liang in the original) as King herb, showcasing its powerful ability to clear Wind from the head and relieve headache. This formula treats all types of Wind headache and demonstrates Bo He's ascending, head-clearing nature at its fullest.

Yin Qiao San 银翘散 Deputy

Yin Qiao San is the most famous formula for early-stage Wind-Heat invasion, which is Bo He's signature indication. Bo He serves as Deputy, working alongside Jin Yin Hua and Lian Qiao to disperse Wind-Heat, clear the head, and benefit the throat. This formula showcases Bo He's core exterior-releasing, throat-benefiting actions.

Sang Ju Yin 桑菊饮 Assistant

Sang Ju Yin treats Wind-Heat cough in its earliest stage. Bo He assists by dispersing exterior Wind-Heat and clearing the head, supporting Sang Ye and Ju Hua. This formula highlights Bo He's role in milder Wind-Heat presentations focused on the Lung system.

Xiao Yao San 逍遥散 Envoy

Xiao Yao San (Free and Easy Wanderer) is the definitive formula for Liver Qi stagnation with Blood deficiency and Spleen weakness. Bo He is used in small quantity as Envoy to vent stagnant Liver Qi and disperse the Heat that arises from constraint. This formula perfectly demonstrates Bo He's secondary but clinically important action of coursing the Liver and resolving constraint.

Comparable Ingredients

These ingredients have overlapping uses — here's how to tell them apart

Chai Hu
Bo He vs Chai Hu

Both Bo He and Chai Hu can disperse Wind-Heat and course the Liver. However, Bo He is stronger at clearing the head, eyes, and throat, venting rashes, and producing a light sweat, making it more suited for exterior Wind-Heat patterns with upper-body symptoms. Chai Hu excels at treating Shao Yang (half-exterior, half-interior) patterns with alternating chills and fever, and at raising Yang Qi to treat prolapse. For Liver Qi stagnation, both are used, but Chai Hu is the primary mover while Bo He assists.

Sang Ye
Bo He vs Sang Ye

Both are cool, acrid herbs that disperse Wind-Heat and clear the head and eyes. Sang Ye is better at moistening dryness in the Lungs (useful for dry cough) and calming Liver Yang rising. Bo He is stronger at promoting sweating, benefiting the throat, venting rashes, and coursing stagnant Liver Qi. Choose Sang Ye when Lung dryness or Liver Yang rising is prominent; choose Bo He when sore throat, skin rashes, or emotional Liver constraint is the main concern.

Chan Tui
Bo He vs Chan Tui

Both disperse Wind-Heat and vent rashes. Chan Tui (cicada moulting) is better at stopping itching, calming Liver Wind and spasms, and clearing the voice in hoarseness. Bo He has broader action: it also clears the head, benefits the throat, and courses the Liver. Chan Tui is preferred when there are convulsions, severe itching, or voice loss; Bo He is preferred for general Wind-Heat exterior patterns and Liver Qi constraint.

Identity & Adulterants

Related species and common adulterations to be aware of when sourcing Bo He

Bo He (Mentha haplocalyx) is most commonly confused with or substituted by Spearmint, known as Liu Lan Xiang (留兰香, Mentha spicata). Spearmint lacks menthol, instead containing carvone as its main volatile component, and has different therapeutic properties (warm rather than cool). Key distinguishing features: authentic Bo He has axillary whorled flower clusters, hairy stems, leaves, and calyces, and a distinct cool menthol aroma; Spearmint has a sweeter, less cooling scent. Peppermint (Mentha piperita, Hu Jiao Bo He) can also be mixed in; it differs in chemistry with more menthyl acetate or pulegone. Due to widespread cultivation and easy hybridization within the Mentha genus, cross-contamination from hybrid varieties is an increasing concern.

Educational content — always consult a qualified healthcare provider or TCM practitioner before using any herb.

Toxicity Classification

Classical Chinese pharmacopoeia toxicity rating for Bo He

Non-toxic

Bo He is classified as non-toxic in the Chinese Pharmacopoeia. Menthol (the primary active constituent) has a wide safety margin, with LD50 values for natural menthol in mice of 5000-6000 mg/kg (subcutaneous injection). Long-term feeding studies in rats showed no carcinogenic effects. At standard decoction dosages, Bo He poses no toxicity concerns. Excessive use may cause excessive sweating and depletion of fluids, which is a functional concern rather than true toxicity.

Contraindications

Situations where Bo He should not be used or requires extra caution

Caution

Yin deficiency with Heat signs (night sweats, dry mouth, tidal fever). Bo He's dispersing and cooling nature can further deplete Yin fluids, as the Ben Cao Jing Shu warns: those with Yin deficiency fever should not take it, as sweating will further exhaust their fluids.

Caution

Exterior deficiency with spontaneous sweating. Bo He is a strong diaphoretic (sweat-promoting) herb that can worsen conditions where the body is already losing fluids through excessive sweating.

Caution

Qi deficiency, especially in patients who are chronically fatigued or weakened. The dispersing nature of Bo He can further scatter already depleted Qi.

Caution

Nursing mothers. Bo He's dispersing properties may reduce lactation and lead to insufficient breast milk production.

Caution

Lung deficiency cold-type cough without Heat signs. Bo He is cool and dispersing and would be inappropriate when the Lungs need warming and consolidating rather than scattering.

Caution

Blood deficiency headache when used alone. The Ben Cao Jing Shu cautions that for headache from Blood deficiency, Bo He should not be used without also combining Blood-nourishing herbs.

Caution

Children with fever due to food stagnation (Shang Shi) or malnutrition (Gan Ji). In these cases the root cause is internal, and dispersing with Bo He is not appropriate.

Special Populations

Important considerations for pregnancy, breastfeeding, and pediatric use

Pregnancy

Use with caution during pregnancy. Pharmacological research has demonstrated that Bo He has anti-implantation, anti-early pregnancy, and uterine-stimulating effects. While not absolutely contraindicated, it should only be used during pregnancy under practitioner supervision when there is a clear clinical indication, and at the lowest effective dose for the shortest duration necessary.

Breastfeeding

Bo He may reduce breast milk production due to its dispersing and cooling nature. Classical sources and modern TCM references caution that nursing mothers should avoid or limit its use, as it may lead to insufficient lactation. If needed for a specific condition such as acute mastitis, it should be used short-term at low doses under practitioner guidance.

Children

Bo He can be used in children at reduced doses (typically one-third to one-half of adult dosage, adjusted by age and body weight). It is commonly found in paediatric formulas for Wind-Heat colds and measles that fail to erupt fully. However, it should not be used in children with Qi deficiency, fever from food stagnation, or malnutrition-related fever. As with adults, prolonged use should be avoided.

Drug Interactions

If you are taking pharmaceutical medications, be aware of these potential interactions with Bo He

CYP3A4 substrates: Peppermint oil (containing menthol, the primary active component of Bo He) has been shown in vitro and in a small clinical trial to moderately inhibit CYP3A4 enzyme activity. This may modestly increase blood levels of drugs metabolized by CYP3A4, including calcium channel blockers (e.g. felodipine, nifedipine), cyclosporine, certain statins, and some benzodiazepines. Clinical significance at standard TCM decoction doses is likely low, but caution is warranted with narrow-therapeutic-index drugs.

Warfarin and anticoagulants: Case reports have described altered INR levels in patients taking warfarin who also consumed significant amounts of menthol. While controlled studies have not confirmed a direct interaction, it is prudent to monitor coagulation parameters if Bo He is used alongside anticoagulant therapy.

Iron supplements: Peppermint oil may inhibit the absorption of iron supplements. If iron supplementation is being taken, it should be separated from Bo He by at least 2 hours.

Dietary Advice

Foods and dietary considerations when taking Bo He

When taking Bo He for dispersing Wind-Heat, avoid greasy, heavy, and fried foods that impede the dispersing function of the herb. Cold and raw foods are acceptable since Bo He is cool in nature and used for Heat conditions. Avoid excessive consumption of sour foods, which have an astringing quality that may counteract Bo He's dispersing action.

Botanical Description

Physical characteristics and morphology of the Bo He source plant

Mentha haplocalyx Briq. is a perennial herbaceous plant in the Lamiaceae (mint) family. It grows up to about 1 metre tall, with characteristic square stems that are purplish-brown or light green and bear fine hairs along the angles. The leaves are opposite, ovate-lanceolate to oblong, 2 to 7 cm long and 1 to 3 cm wide, with coarsely serrated edges above the base. Both leaf surfaces are lightly hairy, and the undersides have small glandular scales visible under magnification that contain the aromatic volatile oil.

The flowers are small, pale purple or white, arranged in whorled clusters (verticillasters) in the leaf axils, a key distinguishing feature from related mint species. The plant spreads vigorously via underground rhizomes and prefers warm, moist, sunny environments. It thrives in loose, fertile soils with a pH of 5.5 to 6.5, and can grow at altitudes up to 2100 metres, though lower elevations produce higher essential oil content.

Sourcing & Harvesting

Where Bo He is sourced, when it's harvested or collected, and how to assess quality

Harvesting season

Summer and autumn, when stems and leaves are lush or flowers have opened to the third whorl. Harvested on clear days, can be cut in two or three rounds per year.

Primary growing regions

The finest quality Bo He historically comes from Jiangsu province, especially the Suzhou, Taicang, and Nantong areas, where it is known as "Su Bo He" (苏薄荷). Li Shizhen recorded in the Ben Cao Gang Mu that Suzhou-grown mint had the thinnest stems and most fragrant aroma, and was best for medicinal use. Zhejiang province is also a major producing region. Bo He is now widely cultivated across China, including in Jiangxi, Anhui, and Sichuan, though quality varies by region. Jiangsu remains the most prized origin (dao di yao cai).

Quality indicators

Good quality Bo He should be dry and complete, with abundant leaves and few thick old stems. The leaves should be deep green on top and grey-green underneath, not yellowed or blackened. When rubbed between the fingers, it should release a strong, clean, cool aromatic fragrance with a distinctly refreshing, pungent-cool taste. The classical standard is "qi qing xiang, wei liang qin" (fragrant aroma, cool penetrating taste). The stems should be thin and fine, not coarse or woody. Specimens from Jiangsu (Su Bo He) are considered the best grade. Avoid material that is predominantly stems with few leaves, smells musty, or has a harsh rather than refreshing flavour.

Classical Texts

Key passages from the classical Chinese medical texts that describe Bo He and its therapeutic uses

Xin Xiu Ben Cao (《新修本草》, Tang Dynasty)

Original: 「主贼风伤寒，发汗。恶气心腹胀满，霍乱，宿食不消，下气。」

Translation: "Governs lurking Wind and Cold Damage, promoting sweating. Treats noxious Qi, fullness and distension of the chest and abdomen, cholera-like disorders, and undigested food accumulation; directs Qi downward."

Ben Cao Gang Mu (《本草纲目》, Li Shizhen, Ming Dynasty)

Original: 「利咽喉，口齿诸病。治瘰疬，疮疥，风瘙瘾疹。」

Translation: "Benefits the throat, and treats various diseases of the mouth and teeth. Treats scrofula, sores and scabies, and Wind-type itchy skin rashes."

Dian Nan Ben Cao (《滇南本草》, Lan Mao, Ming Dynasty)

Original: 「上清头目诸风，止头痛、眩晕、发热。祛风痰，治伤风咳嗽，脑漏，鼻流臭涕。退男女虚痨发热。」

Translation: "Clears the head and eyes of various Wind disorders, stops headache, dizziness, and fever. Dispels Wind-Phlegm, treats cough from Wind invasion, nasal discharge, and foul-smelling nasal mucus. Reduces fever from consumptive deficiency in both men and women."

Ben Cao Xin Bian (《本草新编》, Qing Dynasty)

Original: 「薄荷，不特善解风邪，尤善解忧郁，用香附以解郁，不若用薄荷解郁之更神。薄荷入肝胆之经，善解半表半里之邪，较柴胡更为轻清。」

Translation: "Bo He is not only excellent at resolving Wind pathogens but is especially skilled at resolving melancholy and emotional constraint. Using Xiang Fu to relieve depression is not as wonderfully effective as using Bo He. Bo He enters the Liver and Gallbladder channels, and is adept at resolving pathogens lodged between the exterior and interior, being lighter and more buoyant than Chai Hu."

Historical Context

The history and evolution of Bo He's use in Chinese medicine over the centuries

Bo He was first recorded in Sun Simiao's Qian Jin Shi Zhi (《千金·食治》) during the Tang Dynasty under the name "Fan He Cai" (蕃荷菜), meaning "foreign mint vegetable," suggesting the plant may have been introduced or recognized as distinct from native Chinese mints. It was initially classified as acrid and warm in nature. From the Tang Dynasty onward, Bo He was widely cultivated, and by the Song Dynasty its use had become common in both medicine and daily life.

An interesting shift in understanding occurred over the centuries. Before the Song Dynasty, texts consistently described Bo He as warm in nature, likely because it was associated with other warm, acrid, dispersing herbs like Xiang Ru and Zi Su. It was only in the Southern Song work Lu Chan Yan Ben Cao (《履巉岩本草》) that Bo He was first described as "extremely cool," and by the Qing Dynasty, the consensus settled on the classification of cool (liang) that we use today.

The name "Bo He" (薄荷) itself is thought to be a transliteration of a foreign word, though its exact etymology remains debated. Li Shizhen noted multiple local names including "Ye Xi Hua" (夜息花, night-rest flower), reflecting the plant's calming aromatic qualities. Bo He's role in the famous formula Xiao Yao San (Free and Easy Wanderer) highlights its unique capacity to soothe Liver constraint, a use emphasized by many later physicians who considered it superior to even Chai Hu for this purpose in lighter cases.

Modern Research

4 published studies investigating the pharmacological effects or clinical outcomes of Bo He

1

Comprehensive Review: Botany, Traditional Uses, Phytochemistry, Health Benefits of Mentha haplocalyx (2024)

Tang HP, Zhu EL, Bai QX, Wang S, Wang ZB, Wang M, Kuang HX. Chinese Medicine. 2024; 19:168.

A systematic review consolidating research on Mentha haplocalyx found that its main bioactive compounds include terpenoids, flavonoids, and phenolic acids, with terpenoids being the primary active constituents. In vitro and in vivo studies demonstrated diverse health benefits including neuroprotective, anti-asthmatic, anti-inflammatory, gut health improvement, hypoglycemic, anti-aging, antibacterial, and antioxidant effects.

PubMed
2

Anti-inflammatory Effects of Mentha haplocalyx Phenolic Fraction and Linarin (In Vitro, 2017)

Chen X, Zhang S, Xuan Z, Ge D, Chen X, Zhang J, Wang Q, Wu Y, Liu B. Molecules. 2017; 22(5):811.

The phenolic fraction of Mentha haplocalyx and its constituent linarin were shown to reduce inflammatory mediators (NO, PGE2, TNF-alpha, IL-6, IL-1beta) in LPS-stimulated macrophages by inactivating the NF-kB and MAPK signaling pathways. This provides a mechanistic basis for the herb's traditional use in treating inflammatory conditions.

PubMed
3

Protective Effects of Mentha haplocalyx in Allergic Asthma Mouse Model (Preclinical, 2011)

Wei JR, Wen X, Bible PW, Li Z, Bhatt D, Tang Q. Int Immunopharmacol. 2011; 11(9):1120-1126.

In an ovalbumin-induced mouse model of allergic asthma, Mentha haplocalyx ethanol extract significantly reduced airway inflammation by inhibiting IgE production and Th2-type cytokines (IL-4, IL-5) in bronchoalveolar lavage fluid and lung tissue, and alleviated inflammatory cell infiltration.

PubMed
4

Peppermint Oil as Inhibitor of CYP3A4 Activity In Vitro and In Vivo (RCT, 2002)

Dresser GK, Wacher V, Wong S, Wong HT, Bailey DG. Clinical Pharmacology & Therapeutics. 2002; 72(3):247-255.

A randomized 4-way crossover study in 12 healthy volunteers found that peppermint oil and its main constituents menthol and menthyl acetate produced moderate reversible inhibition of CYP3A4 in liver microsomes. The oil modestly increased felodipine plasma concentrations, suggesting a potential for herb-drug interaction with CYP3A4-metabolized medications.

PubMed

Research on individual TCM herbs is growing but still limited by Western clinical trial standards. These studies provide emerging evidence and should be considered alongside practitioner expertise.