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Tatarian aster

Aster tataricus

Also calledZi wan 紫菀 (Chinese) · Fan huncao (Chinese) · Shion シオン (Japanese) · Gaemichwi 개미취 (Korean)

A tall purple-flowered aster of north-east Asia whose dried root and rhizome, zi wan, has been a Chinese cough and phlegm medicine since the Shennong Bencao Jing. Modern support comes from animal and cell studies only, and animal studies point to liver toxicity at high doses or with long use.

What it is used for

Asthma and wheeze
Limited
Ethanol extracts relaxed guinea-pig airway smooth muscle and showed anti-asthmatic activity in animal models. It appeared in 205 of 218 Chinese prescriptions analysed for cough-variant asthma, but it has not been tested on its own in people.^1,2
Bronchitis
Limited
In animal studies Zi Wan San (root with other herbs) and root extracts reduced airway inflammation; human evidence is limited to multi-herb Chinese formulas.²
Viral infections
Limited
A root extract inhibited influenza A, Newcastle disease and herpes simplex viruses in cell culture and improved survival of mice given lethal influenza when given beforehand. Laboratory and animal work only.⁴
Cough
Traditional
The Chinese Pharmacopoeia (2020) lists it for cough with excessive phlegm, wheezing, chronic cough and coughing up blood. In mice, shionone and epi-friedelanol from the root reduced ammonia-induced coughing and extracts increased phlegm clearance; honey-processed root was more effective than raw. No clinical trials of the herb alone were found.^1,2
Constipation
Traditional
Older Chinese medical records describe it as relieving constipation and difficult urination; untested.^1,2

How it is prepared

decoction

The dried root and rhizome, raw or honey-fried, boiled in water, usually with other herbs in a formula.

Chinese Pharmacopoeia (2020), as cited in a 2025 review: 5–10 g.

Cough

food

In China, Korea and Japan young spring leaves are blanched and eaten as a vegetable; China permits the plant as both food and medicine within a limited scope and dose.

Amounts are as recorded by the named source, not a recommendation.

Safety

Pregnancy: Insufficient data
Breastfeeding: Insufficient data

Toxicity

Reviews describe it as generally considered clinically safe at pharmacopoeial doses, but animal studies point to the liver: the oral LD50 of a 75% ethanol extract in mice was 15.74 g/kg; subchronic dosing in rats (0.34 g/kg/day) caused liver damage concentrated in the petroleum-ether and ethyl-acetate fractions; and one fraction caused acute liver injury and death in mice at 0.052 g/kg. Saponins are haemolytic, so crude extracts are not suitable for intravenous use. Human toxicity data are lacking; risk appears greater at high doses or with long use.

In the healing traditions

Traditional Chinese Medicine
Zi wan (紫菀)
Acrid, bitter and warm, belonging to the Lung channel; used to clear lung qi, calm adverse-rising qi, relieve cough and resolve sputum. The Shennong Bencao Jing says it relieves cough, regulates cold and heat in the chest and calms the five viscera; later materia medica add coughing of blood, pulmonary abscess and children's convulsions. Honey-frying is said to make it better at moistening the lungs and relieving cough.
Shennong Bencao Jing; Xin Xiu Ben Cao; Chinese Pharmacopoeia 2020

Active compounds

shionone: triterpene used by the Chinese Pharmacopoeia as the quality marker; antitussive and anti-inflammatory in animal studies
astins A–P: chlorinated cyclic pentapeptides from the root; structurally similar to the hepatotoxic fungal toxin cyclochlorotine; at least astins C, F and G are made by the endophytic fungus Cyanodermella asteris living in the plant
triterpenoid saponins: considered expectorant; haemolytic, so crude extracts are unsuitable for injection
quercetin, kaempferol, ferulic acid: identified as antiviral constituents of the aqueous fraction in one study

History

Zi wan is recorded in the Shennong Bencao Jing and has been used in Chinese medicine for more than 2,000 years, traditionally processed with honey, vinegar, wine or ginger and today mainly honey- or bran-fried. In 2026 researchers showed that at least some of its signature astin peptides are made not by the plant but by a fungus living inside it.

Sources

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.