☯ TCM Properties

Category: transforming dampness

Temperature: neutral

Taste: pungent

Meridians: spleen, stomach, lung

Functions:

Aromatically Transforms Dampness; Awakens the Spleen and Opens the Appetite; Releases the Exterior and Resolves Summerheat

Traditional Chinese Uses

Pei Lan (eupatorium herb) is a warm, pungent aromatic herb used to transform Dampness, clear Summerheat, and address the heavy, stagnant Dampness accumulation in the Spleen and Stomach. It is used for the Damp-Heat patterns presenting with poor appetite, sweet or sticky taste in the mouth, bad breath, and the heavy-headed, sluggish feeling of Damp obstruction in the middle burner. As a classic Summerheat herb, it is particularly valued during hot, humid seasons for addressing the combined attack of heat and dampness on the digestive system.

Western Herbalism Properties

Actions:

carminativediaphoretic

Relationships

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Botanical Description

Eupatorium fortunei is an aromatic perennial herb in the Asteraceae family, native to eastern Asia including China, Japan, and Korea. The plant grows 40-100 cm tall from a creeping rhizome, with erect, often purple-tinged stems that are simple or branched in the upper portion. The opposite leaves are lanceolate to ovate-lanceolate, 5-12 cm long, with serrate margins and a distinctive sweet, vanilla-like fragrance when crushed; upper leaves are often three-lobed. Small purplish-pink tubular flowers are clustered in dense corymbose heads at the stem tips, blooming in late summer and autumn. In TCM, the aerial parts (Pei Lan) are used as a fragrant, drying herb that transforms dampness, particularly for damp-heat in the middle burner with sticky taste in the mouth.

Active Constituents

Thymol

Monoterpene phenol (volatile oil constituent)

Concentration: 20.81-132.21 micrograms per gram in the leaf and 5.48-19.10 micrograms per gram in the stem by GC-MS/MS; the only one of the four marker volatiles also detectable in the root

The principal phenolic monoterpene of the volatile oil and one of the four compounds used to grade the quality of the crude drug. Total content follows leaves > stems > roots, which is why leaf-rich material is preferred.

p-Cymene

Aromatic monoterpene hydrocarbon (volatile oil constituent)

Concentration: 1.51-25.25 micrograms per gram in the leaf and 1.79-5.90 micrograms per gram in the stem by GC-MS/MS

A major aromatic component of the volatile oil and one of the four Chinese quality markers for the herb. It contributes most of the characteristic odour on which the traditional aromatic damp-transforming action is predicated.

Neryl acetate

Monoterpene ester (volatile oil constituent)

Concentration: 13.77-59.90 micrograms per gram in the leaf and 12.51-40.94 micrograms per gram in the stem by GC-MS/MS

One of the four quantified quality markers of the herb; distributed through both leaf and stem, unlike beta-caryophyllene.

beta-Caryophyllene

Bicyclic sesquiterpene hydrocarbon (volatile oil constituent)

Concentration: 13.36-144.21 micrograms per gram in the leaf; not detected in stem or root by GC-MS/MS

Leaf-restricted sesquiterpene and a quality marker. Its absence from stem and root means stem-heavy or root-contaminated material differs chemically from leaf material.

Intermedine and lycopsamine (with their N-oxides)

1,2-unsaturated retronecine-type pyrrolizidine alkaloids

Concentration: Total pyrrolizidine alkaloids 0.18-61.81 micrograms per gram across 30 batches of the herb and 0.86-36.96 micrograms per gram in 4 commercial finished products (LC-MS/MS against 32 reference standards); intermedine N-oxide and lycopsamine N-oxide were the most abundant

This species does carry the hepatotoxic 1,2-unsaturated pyrrolizidine alkaloid class - the question is settled, not open. Intermedine and lycopsamine N-oxides were cytotoxic to neural progenitor cells in vitro, and intermedine N-oxide impaired their oligodendrogenesis. Levels in the raw herb are in the microgram-per-gram range, far below comfrey-type exposures, but the authors calculated that intake from this herb still exceeds the acceptable daily intake proposed by the EMA.

Echinatine and echinatine N-oxide

1,2-unsaturated retronecine-type pyrrolizidine alkaloids

Concentration: In a total alkaloid extract prepared from the herb, echinatine N-oxide was 29.55 percent and echinatine 17.28 percent of the alkaloid fraction; eight pyrrolizidine alkaloids together accounted for 92.38 percent of it

The dominant alkaloids of a concentrated total alkaloid extract of the herb. Dosing mice with that extract at 25 mg/kg/day for 4 weeks produced raised ALT and AST, hepatocyte damage, fibrosis and apoptosis, with disruption of glycerophospholipid metabolism as the proposed mechanism. Note this describes a concentrated extract, not a conventional decoction dose.

Retronecine, seneciphylline, senkirkine and 7-acetylintermedine N-oxide

Pyrrolizidine alkaloids (retronecine and otonecine types)

Concentration: Detected among the eight pyrrolizidine alkaloids identified in the herb by LC-MS/MS, at lower abundance than intermedine and lycopsamine N-oxides

Minor pyrrolizidine alkaloids of the herb. Senkirkine is an otonecine-type alkaloid and seneciphylline a macrocyclic diester, both regarded as more potently hepatotoxic per unit than the monoester lycopsamine group, so their presence matters out of proportion to their share of the total.

⚠ Drug Interactions

Other pyrrolizidine-alkaloid-containing herbs (e.g. Gynura segetum, Tussilago farfara, Senecio and Symphytum species)

Major Evidence: Probable

Pei Lan contains 1,2-unsaturated pyrrolizidine alkaloids (intermedine, lycopsamine, echinatine, rinderine and their N-oxides, plus traces of seneciphylline and senkirkine), confirmed by LC-MS/MS in 30 herb batches and 4 finished products at 0.18-61.81 micrograms per gram. Alkaloid toxicity in this class is dose-cumulative: the free bases are oxidised in the liver to dehydropyrrolizidine esters that alkylate proteins and DNA in sinusoidal endothelial cells. Adding a second pyrrolizidine-containing herb simply adds to the same total. The authors of the LC-MS/MS survey concluded that intake from this herb alone already exceeded the EMA acceptable daily intake, and that chronic use warrants caution even though short-term use is unlikely to cause acute injury.

Clinical note: Do not stack Pei Lan with other pyrrolizidine-alkaloid herbs, and do not prescribe it as a long-term daily herb. Keep courses short. Avoid in pregnancy, in infants, in existing liver disease, and in anyone with unexplained abdominal distension, ascites or tender hepatomegaly.

Hepatotoxic drugs (e.g. methotrexate, isoniazid, amiodarone, high-dose paracetamol/acetaminophen)

Moderate Evidence: Possible

A total alkaloid extract of this species given to mice at 25 mg/kg/day for 4 weeks lowered body and liver weight, raised ALT and AST, and produced hepatocyte damage, fibrosis, accelerated apoptosis, raised IL-6, TNF-alpha, NF-kB and iNOS, and an increased GSSG/GSH ratio. Pyrrolizidine alkaloid bioactivation consumes glutathione, so the herb reduces the same hepatic reserve that protects against paracetamol and other reactive-metabolite hepatotoxins. No human interaction reports exist; this is extrapolation from animal data.

Clinical note: Avoid combining with known hepatotoxic drugs, particularly for courses longer than a few weeks. If co-use is unavoidable, check liver function before and during treatment and stop the herb at any rise in transaminases.

CYP3A4 inducers (e.g. rifampicin, carbamazepine, phenytoin, St John's wort)

Theoretical Evidence: Theoretical

1,2-unsaturated pyrrolizidine alkaloids are not toxic as absorbed; they require hepatic cytochrome P450 oxidation, predominantly CYP3A4, to dehydropyrrolizidine esters, which then form pyrrole-protein and pyrrole-DNA adducts. Inducing that pathway increases the fraction routed to bioactivation. This mechanism is established for the alkaloid class in general, and this species is confirmed to contain those alkaloids, but no study has tested the induction interaction with Eupatorium fortunei specifically. It is stated here as mechanism, not as observed fact.

Clinical note: Treat concurrent enzyme-inducing drugs as a reason to prefer a non-pyrrolizidine damp-transforming substitute (for example Huo Xiang, Agastache rugosa) rather than to adjust the Pei Lan dose.

Dosage

Form	Amount	Frequency	Duration	Population	Notes
decoction	3–10 g	Daily	—	—	中国药典 2020 【用法与用量】3～10g。【性味与归经】辛，平。归脾、胃、肺经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value.

Dui Yao — Herb Pairs

The classical two-herb combinations this herb appears in, each with an action neither herb has alone.

with Huo Xiang 藿香

Two aromatic herbs that together more strongly transform turbid dampness, awaken the spleen and release summerheat-dampness.

Summerheat-dampness, sweet or sticky taste in the mouth, nausea, greasy coating.

Named pairing — Lü Jingshan, Shi Jinmo Dui Yao

Evidence Tier

Limited evidence · 2 studies

Recorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.

Systematic review / meta-analysis

0

Randomized controlled trial

0

Other clinical trial

0

Observational / case report

0

In vitro / animal

2

2 verified · 0 unverified

Show 2 studies

Analysis of pyrrolizidine alkaloids in Eupatorium fortunei Turcz. and their in vitro neurotoxicity
Integrative Metabolomics and Proteomics Detected Hepatotoxicity in Mice Associated with Alkaloids from Eupatorium fortunei Turcz.

Other / unclassified

0

Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description

Clinical Studies

Analysis of pyrrolizidine alkaloids in Eupatorium fortunei Turcz. and their in vitro neurotoxicity

Zhang Yan; Yang Fei-Fei; Chen Huan; Qi Yao-Dong; Si Jian-Yong; Wu Qing; Liao Yong-Hong (2021) Food and Chemical Toxicology in vitro Verified: In vitro / animal

LC-MS/MS screening against 32 reference standards identified eight pyrrolizidine alkaloids in this species, including intermedine, intermedine N-oxide, lycopsamine, lycopsamine N-oxide, retronecine, seneciphylline, senkirkine and 7-acetylintermedine N-oxide, with the intermedine and lycopsamine N-oxides most abundant. Total alkaloid content ranged from 0.18 to 61.81 micrograms per gram across 30 herb batches and from 0.86 to 36.96 micrograms per gram in 4 commercial finished products. Intermedine and lycopsamine N-oxides were cytotoxic to neural progenitor cells, and intermedine N-oxide impaired their oligodendrogenesis. Calculated intakes exceeded the EMA acceptable daily intake; the authors judged short-term use unlikely to cause acute toxicity but flagged chronic use as a concern.

DOI: 10.1016/j.fct.2021.112151 Link

Integrative Metabolomics and Proteomics Detected Hepatotoxicity in Mice Associated with Alkaloids from Eupatorium fortunei Turcz.

Zan Ke; Lei Wei; Li Yaolei; Wang Ying; Liu Lina; Zuo Tiantian; Jin Hongyu; Ma Shuangcheng (2022) Toxins animal Verified: In vitro / animal

A total alkaloid extract of the herb, in which eight pyrrolizidine alkaloids made up 92.38 percent of the alkaloid fraction (echinatine N-oxide 29.55 percent, echinatine 17.28 percent, lycopsamine N-oxide 14.47 percent), was given to mice at 25 mg/kg/day for 4 weeks. It reduced body and liver weight, raised ALT and AST, and caused hepatocyte damage, fibrosis and accelerated apoptosis, with elevated IL-6, TNF-alpha, NF-kB and iNOS and a raised GSSG/GSH ratio. Combined metabolomics and proteomics pointed to disrupted glycerophospholipid metabolism, with dysregulation of LPGAT1, CHKB, CEPT1 and PLD4, alongside disturbed oxidative phosphorylation and glutathione metabolism.

DOI: 10.3390/toxins14110765 Link

Historical Texts

Shen Nong Ben Cao Jing

Han dynasty

Lists lan cao in the upper class: acrid and neutral in flavour, said to open the water passages, kill gu toxin and ward off the inauspicious, with long use said to boost qi, lighten the body and open the spirit-brightness. Lan cao is the classical name later assigned to this species, though early Chinese materia medica did not distinguish it from related aromatic plants as sharply as modern botany does.

Huang Di Nei Jing Su Wen, chapter Qi Bing Lun (Discussion of Strange Diseases)

Warring States to Han dynasty

For pi dan, the pattern of a persistent sweet taste in the mouth arising from fluids retained in the Spleen, the text prescribes treatment with lan to remove stale qi. This passage is the origin of Pei Lan's core indication of a sweet or greasy taste in the mouth with damp obstruction of the middle burner.

References

Ma Jian-Qiang; Sun Yan-Ping; Wu Tian-Yuan; Yuan Hui-Yue; Li Xin-Lan; Huang Hua; Wu Li-Hong; Wang Zhi-Bin; Kuang Hai-Xue. Eupatorium fortunei Turcz.: An Updated Review on the Botany, Phytochemistry, Pharmacology, and Toxicology . Molecules (2026) [DOI]
Nan Guanjun; Zhang Lina; Liu Zhengzheng; Liu Yu; Du Yan; Zhao Hongwen; Zheng Hongxia; Lin Rong; Yang Guangde; Zheng Shaohua. Quantitative Determination of p-Cymene, Thymol, Neryl Acetate, and β-Caryophyllene in Different Growth Periods and Parts of Eupatorium fortunei Turcz. by GC-MS/MS . Journal of Analytical Methods in Chemistry (2021) [DOI]
Tori Motoo; Ohara Yukiko; Nakashima Katsuyuki; Sono Masakazu. Thymol Derivatives from Eupatorium fortunei . Journal of Natural Products (2001) [DOI]
Chang Chun-Hao; Wu Semon; Hsu Kai-Cheng; Huang Wei-Jan; Chen Jih-Jung. Dibenzofuran, 4-Chromanone, Acetophenone, and Dithiecine Derivatives: Cytotoxic Constituents from Eupatorium fortunei . International Journal of Molecular Sciences (2021) [DOI]
Miao Lei; Wei Quan-Hao; Wang Shu-Ting; Sun Ping; Zhang Hua. Chemical constituents from Eupatorium fortunei and their anti-inflammatory evaluation by in silico and experimental approaches . Fitoterapia (2023) [DOI]
Schrenk Dieter. Toxicology of pyrrolizidine alkaloids . Food and Chemical Toxicology (2020) [DOI]

Pei Lan

Traditionally used for

Cautions & contraindications