← The ApothecaryAraceaetuber (always processed before use)Fact-checked 24 October 2026

Significant riskRaw tuber causes violent irritation of the mouth and throat, loss of voice and vomiting; reviews also report miscarriage. In animals, raw powder caused inflammation, kidney damage and embryotoxicity, and the crystal–lectin fraction is highly toxic (mouse oral LD50 about 16 mg/kg). Processing with ginger, alum, liquorice or lime is the traditional way of reducing its toxicity, and soaking in lime water denatures the lectin. Not for home preparation.In an emergency, call your local emergency number or poison centre.

Crow-dipper

Pinellia ternata

Also calledBan xia (Chinese) · Hange (Japanese, Kampo)

In older monographsPinelliae Rhizoma (drug name)

Ban xia, the tuber of a small aroid, is one of the main Chinese herbs for phlegm, cough and vomiting, and appears in many classical formulas used in China, Japan and Korea. Raw, it is toxic: needle-like calcium oxalate crystals and a lectin violently irritate the mouth and throat, so it is only used after traditional processing with ginger, alum, liquorice or lime. Trials exist only for multi-herb formulas.

What it is used for

Nausea and vomiting
Limited
A 2024 meta-analysis of 16 Chinese randomised trials (1,246 patients) found that adding Xiao ban xia tang (processed pinellia with fresh ginger) to standard antiemetics improved relief of chemotherapy-induced vomiting (risk ratio 1.35) and nausea (RR 1.23) compared with antiemetics alone. The authors call for larger rigorous trials; the effect of pinellia alone is not tested.¹
Cough
Traditional
In Chinese medicine it dries dampness and transforms phlegm, for cough and asthma with copious phlegm; first recorded in the Shennong Bencao Jing. Antitussive and expectorant effects have been shown only in animal models.²
Diarrhoea
Against
Hangeshashinto (Kampo; Ban xia xie xin tang, 'Pinellia decoction for draining the heart') has been tested to prevent irinotecan chemotherapy diarrhoea. A 2023 meta-analysis of three trials found it did not reduce severe or mild diarrhoea compared with other treatments (low-quality evidence).⁴

How it is prepared

decoction

Processed tuber decocted with fresh ginger as Xiao ban xia tang, a two-herb formula from Zhang Zhongjing's Han-dynasty writings used for vomiting for about 1,800 years.

Nausea and vomiting

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

Safety

Pregnancy: Avoid
Breastfeeding: Insufficient data
Children: No data found.

Do not use if

Raw (unprocessed) tuber must not be taken by mouth
Pregnancy: raw pinellia is linked to miscarriage, and animal studies show embryotoxicity

Side effects

Unprocessed: stinging and burning of mouth and throat, loss of voice, vomiting

Dangerous lookalikes

Commercial ban xia is adulterated with related aroids such as Typhonium flagelliforme, Arisaema erubescens and Pinellia pedatisecta.

In the healing traditions

Traditional Chinese Medicine
Ban xia (半夏)
Acrid, warm and toxic; enters the spleen, stomach and lung channels. Dries dampness and transforms phlegm (cough and asthma from damp or cold phlegm), and 'downbears counterflow to stop vomiting'. The Chinese Pharmacopoeia includes three processed forms: Fa ban xia (soaked with liquorice and lime), Jiang ban xia (boiled with ginger and alum, favoured for vomiting) and Qing ban xia (processed with alum).
Shennong Bencao Jing (Han dynasty); Zhang Zhongjing, Jin gui yao lue (Xiao ban xia tang)
Kampo
Hange
An ingredient of Kampo formulas such as Hangeshashinto (TJ-14), the Japanese form of Ban xia xie xin tang, used among other things for chemotherapy-related gut symptoms.

Active compounds

needle-like calcium oxalate crystals (raphides): with the lectin, the main toxic principle; cause mouth, throat and eye irritation and inflammation
Pinellia lectin (12 kDa protein): inflammatory toxin; denatured by soaking in lime water during processing
nucleosides and alkaloids (guanosine, adenosine, l-ephedrine and others): used as quality markers; their role in the effects is unclear

History

Ban xia was recorded in the Shennong Bencao Jing (Han dynasty) for cough, excessive phlegm, nausea and vomiting, and swellings from poison, and its toxicity was noted there too. Zhang Zhongjing's Xiao ban xia tang paired it with fresh ginger; ginger is also one of the adjuvants used to process the tuber, reducing its toxicity and strengthening its anti-vomiting effect.

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.