Inula japonica (Inula japonica): Benefits, Dosage, Safety & Evidence

Frequently asked questions

How does Inula japonica work as an expectorant?

Inula japonica contains active compounds including britannin, quercetin, isorhamnetin, and inulin, which contribute to its expectorant properties. These compounds are believed to help thin and loosen mucus in the respiratory tract, making it easier to expel. The herb stimulates bronchial secretions and may reduce inflammation in the airways. In Traditional Chinese Medicine, this mechanism is described as 'descending lung qi' and transforming phlegm. Evidence level: C (preliminary research).

Does Inula japonica interact with any medications?

There is limited clinical data on drug interactions with Inula japonica. Due to its potential effects on respiratory secretions and traditional use as an antiemetic, it may theoretically interact with antitussive medications or drugs affecting the gastrointestinal system. Individuals taking blood thinners should exercise caution, as quercetin content may affect platelet aggregation. Always consult a healthcare provider before combining Inula japonica with prescription medications. Evidence level: C (theoretical based on constituent properties).

What is the recommended dosage for Inula japonica?

The typical adult dosage for Inula japonica is 3-9 grams of dried flowers prepared as a decoction. This traditional dosage is based on Traditional Chinese Medicine practice and should be prepared according to standard herbal decoction methods. Dosage may vary depending on the specific formulation and condition being treated. Consult a qualified herbalist or healthcare provider for personalized dosing guidance. Evidence level: Traditional.

Is Inula japonica safe to use during pregnancy?

Inula japonica is considered unsafe during pregnancy and should be avoided. Traditional Chinese Medicine contraindications include use in cases of Yin deficiency. The herb's effects on the uterus and developing fetus have not been adequately studied in clinical trials. Women who are pregnant, nursing, or planning to become pregnant should not use Inula japonica without explicit guidance from a qualified healthcare provider. Evidence level: Traditional/Expert consensus.

What conditions does Inula japonica treat in Traditional Chinese Medicine?

Inula japonica is primarily used in Traditional Chinese Medicine for conditions involving phlegm accumulation, nausea, and respiratory disorders. It is classified as an expectorant and antiemetic herb, traditionally prescribed for productive coughs, wheezing, and feelings of chest congestion. The herb is also used to address nausea and vomiting. In TCM theory, it helps 'descend lung qi' and transform phlegm-dampness. Evidence level: C (traditional use supported by preliminary research).

What are the side effects of Inula japonica?

Inula japonica may cause throat irritation due to the presence of fine hairs on the plant material, which can be minimized by proper preparation and straining. Allergic reactions are possible, particularly in individuals with known allergies to plants in the Asteraceae family, such as ragweed. Those with Yin deficiency according to TCM principles should avoid this herb. Discontinue use if adverse reactions occur. Evidence level: Traditional/Case reports.

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 30 PubMed articles · model: gemma4:31b

Summary

Inula japonica Thunb. is a medicinal plant used in traditional Chinese and Korean medicine, primarily recognized for its anti-inflammatory, antioxidant, and respiratory therapeutic effects [PMID:33961997, 38457106].

Background

Inula japonica Thunb. (also known as Flos inulae or Xuan Fu Hua) is a plant of the Asteraceae family included in the Chinese Pharmacopoeia (2020 edition) [PMID:33961997]. It is widely distributed across Asia and is used as a botanical medicine in China and Korea [PMID:33961997].

Traditional uses

In traditional Chinese medicine, it is used for water removal, reduction in nausea, prevention of vomiting, and the treatment of cold-related coughs, sputum, wheezing coughs, belching, and other related diseases [PMID:33961997]. It is also used to treat inflammatory diseases [PMID:35034149].

Active compounds

The plant contains a diverse array of sesquiterpenoids, including sesquiterpene lactone dimers such as Japonicone A [PMID:35034149, 24387187], neojaponicone B, and inulanolide E [PMID:25617784]. Other identified compounds include alantolactone, isoalantolactone [PMID:24288468], britanin [PMID:37732549], eupatin [PMID:37298159], and phenolic acids such as caffeoylglucaric and caffeoylquinic acids [PMID:40407292]. Flavonoids (e.g., quercetin, kaempferol) and polysaccharides (e.g., IJP70-1) are also present [PMID:30156801, 37364807].

Mechanism of action

Mechanisms include the suppression of neuroinflammation and recovery of HPA-axis dysfunction [PMID:38457106], inhibition of the JAK-STAT signaling pathway in airway inflammation [PMID:39854818], and downregulation of the SRC/EGFR/MAPK signaling pathway via PKC-α targeting [PMID:40480001]. It also acts by inhibiting soluble epoxide hydrolase (sEH) to ameliorate pulmonary fibrosis [PMID:32663670, 36150346] and suppressing MAPK/NF-κB and activating Keap1/Nrf2 pathways to reduce oxidative stress [PMID:36617177].

Clinical evidence

Evidence DDepression

Inulae Flos demonstrated anti-depressive effects by suppressing neuroinflammation and recovering HPA-axis dysfunction in mice models [PMID:38457106]

Evidence DAsthma/Airway Inflammation

Water extract and ethanol extracts reduced airway hyper-responsiveness, inflammatory cell infiltration, and MUC5AC production in mouse models [PMID:39854818, 37597674, 37960252]

Evidence DPulmonary Fibrosis

Extracts significantly restored lung function and decreased collagen deposition by inhibiting soluble epoxide hydrolase in bleomycin-induced mouse models [PMID:32663670]

Evidence DAcute Lung Injury (ALI)

Alleviated inflammation and oxidative stress by inactivating MAPK/NF-κB and activating Keap1/Nrf2 pathways in LPS-induced mice [PMID:36617177, 36150346]

Evidence DCancer

Sesquiterpene lactones and polysaccharides showed cytotoxic and anti-tumor activities against various cell lines (e.g., HepG2, SMMC-7721) and in zebrafish models [PMID:24387187, 36999317, 37364807]

Evidence D

Safety & adverse effects

Alantolactone and isoalantolactone have been reported to have no significant toxicity [PMID:24288468].

Drug interactions

Xuan-Fu-Hua decoction significantly increased the growth inhibition and apoptosis of liver cancer cells when co-administered with 5-fluorouracil (5-FU) [PMID:35966306].

Evidence summary

The current evidence is primarily based on in vitro cell studies and in vivo animal models (mice, zebrafish), indicating strong pharmacological potential for anti-inflammatory and anti-fibrotic activities, but lacks human clinical trial data.

PubMed sources

1.PMID: 38457106 (2024) — Inulae Flos has Anti-Depressive Effects by Suppressing Neuroinflammation and Recovering Dysfunction of HPA-axis. · Molecular neurobiology
2.PMID: 40480001 (2025) — 1-O-Acetylbritannilactone exerts anti-inflammatory and anti-MUC5AC effects by targeting PKC-α and downregulating the SRC/EGFR/MAPK signaling pathway. · International immunopharmacology
3.PMID: 33961997 (2021) — A review of the botany, traditional uses, phytochemistry, and pharmacology of the Flos Inulae. · Journal of ethnopharmacology
4.PMID: 35966306 (2022) — Transcriptomic and network pharmacology approaches revealed possible mechanisms underlying the 5-fluorouracil (5-FU)-sensitizing effect of Xuan-Fu-Hua decoction treatment on liver cancer cells. · Translational cancer research
5.PMID: 24387187 (2014) — Inula sesquiterpenoids: structural diversity, cytotoxicity and anti-tumor activity.

Inula japonica

Sources & Citations

Calculate a safe dose of Inula japonica