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Traditional Chinese medicine

AgastacheAgastache rugosa (the Chinese pharmacopoeial huo xiang is Pogostemon cablin)

Huo xiang is the aromatic lead of Huo Xiang Zheng Qi; its oral liquid beat placebo in a 212-person IBS-D trial (response gap 0.29), but the herb alone is untested.

Botanical name
Agastache rugosa (the Chinese pharmacopoeial huo xiang is Pogostemon cablin)
Part used
aerial parts (leaf and flowering tops), dried
Also called
pinyin Huo xiang (Guang huo xiang for Pogostemon; Tu huo xiang for Agastache) (藿香 / 广藿香); Korean mint, Patchouli herb (Pogostemon cablin), Pogostemonis herba
Used in
Traditional Chinese medicine
Taken for
Nausea, Indigestion, Bloating, Loose stools and diarrhea
Sold as
decoction, oral liquid, capsules, pill, granule extract, dried herb

The plant

Huo xiang is a name that covers two different plants. The Chinese Pharmacopoeia drug, usually sold as guang huo xiang, is the dried aerial part of Pogostemon cablin, the patchouli plant. A review in the American Journal of Chinese Medicine calls it an aromatic, damp-resolving drug and lists 174 components in the plant, including 66 terpenes and 40 flavonoids. The second plant is Agastache rugosa, sometimes called Korean mint, the only Agastache species native to East Asia, according to a review in Plants; Chinese sources call it tu huo xiang.

So a label that says only huo xiang or agastache can mean either. The herb is dried leaf and flowering tops, taken in a short decoction, as a granule extract, as an oral liquid, or as a capsule or pill. It is the lead herb of Huo Xiang Zheng Qi San, a formula that also contains perilla leaf, angelica dahurica, tangerine peel, white atractylodes, processed pinellia, magnolia bark and poria.

How the traditions use it

Traditional Chinese medicine (about TCM)

Huo xiang is acrid and slightly warm in the materia medica, entering the spleen, stomach and lung channels, with the actions of aromatically transforming dampness, harmonizing the middle and stopping vomiting, and releasing the exterior in what the texts call summer dampness. A review of Pogostemon says the plant is usually used for vomiting, chest tightness, tiredness, abdominal pain, diarrhea and headache. For the gut the tradition reaches for it when it sees cold and dampness lodged in the middle after a chill or heavy, damp weather: nausea, vomiting, a stuffy chest and abdominal fullness with loose stools. Huo Xiang Zheng Qi San is written for exactly that picture. Summer dampness and cold-dampness are pattern terms from the texts.

What is in it

For Pogostemon, a Chinese review counts 174 components: 66 terpenes, 6 pyrones, 40 flavonoids, 21 phenylpropanoids, 9 steroids, 4 polysaccharides and 28 others. Laboratory work reports effects on the gastrointestinal tract, inhibition of pathogenic microorganisms and anti-inflammatory activity. For Agastache, a second review reports mostly flavonoids and phenolic acids, with volatile phenylpropanoids and monoterpenes, and antioxidant, antimicrobial, cytotoxic and cardioprotective effects in laboratory studies. These are cell and animal findings, and neither review shows a gut result in people.

What the human trials show

We could not find a controlled trial of Pogostemon or Agastache herb alone for a gut outcome. The human data are trials of Huo Xiang Zheng Qi products, which contain it with other herbs.

The larger one is a double-blind trial in diarrhea-predominant IBS at 14 Chinese hospitals. A total of 212 adults were randomized, 108 to Huo Xiang Zheng Qi oral liquid and 104 to placebo, 20 ml twice daily for 4 weeks. The adequate-relief response rate was higher with the formula, with a rate difference of 0.29 (95% CI 0.14 to 0.43), and the IBS symptom severity score fell by 10.92 points more (95% CI 2.90 to 18.93). No serious adverse events occurred. The manufacturer supplied the product and had no role in analysis or reporting.

A smaller, exploratory multicenter trial in 60 chemotherapy patients added the oral liquid to a 5-HT3 blocker and dexamethasone during a multiday cisplatin regimen. Complete response in the acute phase was 63.33 percent on the formula and 33.33 percent on placebo (p = 0.020), and the number of days without nausea or vomiting over the whole period was 18.10 against 12.13 (p = 0.002).

Not tested: huo xiang alone for dyspepsia or diarrhea, the formula against standard IBS-D drugs, and whether the Pogostemon or the Agastache version matters.

StudyDoseWhat it found
Multicenter double-blind RCT, 212 adults with IBS-D (Huo Xiang Zheng Qi oral liquid vs placebo) PMID 4129732120 ml twice a day for 4 weeksAdequate-relief response difference 0.29 (95% CI 0.14 to 0.43); IBS-SSS mean difference -10.92; no serious adverse events
Exploratory multicenter RCT, 60 patients on multiday cisplatin (oral liquid plus standard antiemetics vs placebo plus antiemetics) PMID 36999940Oral liquid with a 5-HT3 blocker and dexamethasoneAcute complete response 63.33% vs 33.33% (p = 0.020); days without nausea or vomiting 18.10 vs 12.13 (p = 0.002)
Review of Pogostemon cablin: traditional uses, chemistry and pharmacology PMID 35282804Not applicable174 components; laboratory effects on the gastrointestinal tract, microbes and inflammation
Review of Agastache species: chemistry and therapeutic properties PMID 37631149Not applicableFlavonoids, phenolic acids and volatile oil; antioxidant, antimicrobial and other laboratory effects

How much the studies and the texts used

In the IBS-D trial, Huo Xiang Zheng Qi oral liquid was given as 20 ml twice a day for 4 weeks; the abstract of the chemotherapy trial does not state the dose. The traditional preparation of the dried herb is a short water decoction or infusion made with the other herbs of the formula and drunk warm in divided doses. Oral liquid, capsule, pill and granule forms of Huo Xiang Zheng Qi are sold ready-made, and their ingredient lists differ between manufacturers. A single-herb extract of patchouli or Korean mint has no trial-based dose for any gut symptom.

Doses here describe what studies and pharmacopoeias used. They are not a recommendation for any person; a clinician or pharmacist who knows your medicines and conditions is the right person to ask.

Side effects and cautions

The IBS-D trial reported no serious adverse events, and the chemotherapy trial described the formula as feasible and safe when combined with standard antiemetics. Neither plant has pregnancy or breastfeeding data in the sources we read. The review of Pogostemon lists no toxicity finding in its abstract, and the review of Agastache describes its studies as laboratory findings. Because the name huo xiang covers two different plants and Huo Xiang Zheng Qi products differ between manufacturers, a label that does not say which plant or which ingredients were used cannot be matched to either plant’s research.

Interactions

The sources we read describe no interaction between patchouli herb or Korean mint and a medicine, and we found no study designed to test one. Huo Xiang Zheng Qi products contain several other herbs, including pinellia, magnolia bark and licorice, so the interaction notes for those herbs apply to the finished product, and the ingredient list varies between manufacturers and between the liquid, capsule and pill forms.

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Often paired or compared

TCM Perilla Perilla frutescens TCM Pinellia Pinellia ternata TCM Magnolia bark Magnolia officinalis TCM Atractylodes Atractylodes macrocephala (bai zhu); A. lancea (cang zhu) TCM Amomum (sha ren) Wurfbainia villosa (syn. Amomum villosum)

The questions that come up

Is huo xiang patchouli?

In the Chinese Pharmacopoeia, yes: guang huo xiang is Pogostemon cablin, the patchouli plant. Agastache rugosa, or Korean mint, is a different plant sold as tu huo xiang.

What is Huo Xiang Zheng Qi used for in the texts?

The texts use it for cold and dampness in the middle after a chill: nausea, vomiting, abdominal fullness and loose stools. That is the tradition’s description, not a measured effect.

Does it work for IBS with diarrhea?

In a double-blind trial in 212 adults, the oral liquid beat placebo on adequate relief by a rate difference of 0.29 over 4 weeks, with no serious adverse events. The product was a multi-herb formula, so the result is not specific to huo xiang.

Who supplied the product used in the trial?

The manufacturer supplied the investigational product and, according to the report, had no role in the design, analysis or publication of the results.

Has huo xiang been tested alone?

We could not find a controlled trial of patchouli herb or Korean mint alone for a digestive symptom. Reviews describe laboratory effects on the gut, microbes and inflammation.

Sources