Chinese Name : 半夏

Latin Name : Rhizome Pinelliae

Overview

This herb is the dried stem tuber of Pinellia ternate (Thumb.) of the family Araceae. It is grown in most parts of China. The tuber is harvested in summer and autumn, washed clean and dried in the sun. In common practice, pinellia tuber is pharmaceutically processed with fresh ginger juice and alum. The processed herb is called Zhi ban xia. The processed herb is antifebrile, antitussive, a antiemetic, echolic, antimalarial, astringent, and a mild laxative.

Pinellia tuber is warm, and is used to resolves Cold phlegm and it helps expectorate thin phlegm

Use of Pinellia Tuber in TCM

Pungent in taste and warm, and slightly toxic (the fresh herb), it acts on the spleen, stomach, and lung meridians

Effects, Medicinal Uses and Combinations

1. Eliminates Dampness and resolves Cold phlegm:

· For treating profuse phlegm accumulation, coughs, and the adverse upward flow of Qi and vertigo due to malfunction of the spleen and Dampness, pinellia tuber is commonly prescribed with tangerine peel and poria, as Er Chen Tang

· For resolving Cold phlegm, it is customarily used with dry ginger and asarum herb (xi xin).

· For resolving yellow phlegm of Heat nature, fever, and infections of the lungs, scute root and trichosanthes are used

1. Relieves stuffness and distension in the chest, and resolves masses: for treating globus hystericus, manifested clinically as a feeling of a foreign body remaining in the throat that seems neither able to be swallowed nor spat out, pinellia tuber is used with magnolia bark, poria, ginger, and perilla leaf, as in Ban Xia Hou Po Tang.

3. Eliminates nausea and vomiting during pregnancy: pinellia tuber normalize the adverse upward movement of stomach-Qi. It is used with amomum fruit and perilla stem to reduce nausea and vomiting during pregnancy.

Dosage

In a decoction of 3 to 9 g.

Precautions

People who are yin deficient or with any kind of blood disorder or dry cough should avoid this herb. Long-term use this herb is not recommended. Do not take the fresh herb. it must be properly processed according to TCM methods.

Side Effects and Toxicity

The crude herb causes severe irritation of the mucous membranes in the mouth, pharynx, and digestive tract, which causes aphasia, salivation, spasms,dyspnea, asphyxia and, with an overdose, even death.

Chemical Constituents

The tuber contains irritable substances including beta-sitosterol-d-glucoside, 3,4-dihydroxybenzaldehyde, cholin, and homogentisic acid. Other ingredients include glutamic acid, arginines, aspartic acid and alkaloids, essential oil, beta-ephedrine, arginine, and beta-aminobutric acid.

Pharmacological Findings

1. The processed tuber demonstrated a significant antitusive effect against coughs induced by intrapleural injection of iodine or by electrostimulation of the sperior laryngeal nerve.

2. Antiemetic effect. The processed pinellia tuber showed antiemetic action against vomiting induced by apomorphine digitalis or copper sulfate. The mechanism may be due to CNS sedation.

3. The extract of processed pinellia tuber neutralized the toxicity caused by strychnine or acetylcholine.

4. Increases the pain threshold. It is good for toothaches.

5. Lowers intraocular pressure. The pinellia tuber decoction decreases ocular pressure. It may be helpful in treating glaucoma.