It is a perennial herb in Araceae, 15 to 35cm high, with tuber nearly in spherical shape, and 0.5 to 3.0cm in diameter. TCM wise, the medicinal part is the tuber, namely Rhizoma Pinelliae Ternatae (Thunb.) Breit.

The dried pinelliae tuber is spherical, semiorbicular, or oblique, 0.8 to 2cm in diameter. Surface is white or light yellow, with yellow spotted residual cortex. The top is mostly round and flattened, with yellowish brown depressed stem scars in the middle and dense brown pit-shape fibril scars around, and underneath is the blunt sleek end. The quality is solid and compact. The kidney-shaped vertical section is pure white and with fine mealiness, but grayish white or with yellow streaks in older ones or in those unfitting the drying process. Medicinally the preferred one is bigger, clean white, solid and with fine mealiness.

WHAT'S IT USED FOR?
From the perspective of Traditional Chinese Medicine (TCM), it is acrid, warm, and toxic in nature and covers meridians of lung, spleen, and stomach. Main functions are to dry dampness and transform phlegm, descend reversed Qi and stop vomiting, and relieve oppression and resolve hard mass. Main usage and indications are cough and dyspnea due to excessive phlegm, dizziness and palpitation caused by phlegm and fluid retention, wind-phlegm Vertigo, Headache and coma due to blocking of the respiratory system, nausea and vomiting, distention and fullness in chest, and globus hysteriocus. In addition, externally it is used for swelling and ulcer, pyogenic infections, and venomous snake bite. Usual dosage is 4.5 to 12 grams.

Pinellia rhizome

RELATED CHINESE HERBAL FORMULAS 
This herb has been widely used in many herbal remedies for a variety of diseases, among which, the followings are the most famous.

Ban Xia Hou Po Tang (Wan), or Banxia Houpo Tang, from Synopsis of Prescriptions of the Golden Chamber (Jin Gui Yao Lue), is one of the exclusive cures for imagined bolus in throat, which, in the sight of TCM, refers to the status that sputum and saliva obstructing the throat, but actually nothing there but imagined abnormal feeling. Women are prone to this condition, often accompanied with symptoms and signs of lumps in the throat, emotional stagnation, choking sensation in chest, white and greasy coating, and slippery stringy pulse. Now this herbal prescription is frequently used in treatments for pharyngeal neurosis and chronic pharyngitis diagnosed by modern medicine.

Ban Xia Xie Xin Tang (Wan) is designed to lever cold and heat, reduce distension, and dissipate nodules. Main indication is the so-called Pi-syndrome, manifesting feeling fullness and distension in the upper abdomen but no pain, or vomiting, bowel sound, Diarrhea, and slightly yellow and greasy coating. Now this herbal formula is often used in treatments for acute and chronic gastroenteritis, chronic colitis, chronic hepatitis, and earlier period cirrhosis, which fall into the scope of deficiency of middle-Jiao and intermingling with cold and heat in TCM.

Ban Xia Bai Zhu Tian Ma Tang is formulated to alternate warm with cool, give both reinforcing and reducing, invigorate spleen and dry dampness, and transform phlegm and dispel wind. Main symptoms are headache and coma due to blocking of the respiratory system, coughing up sticky mucus, dizziness, annoyance, nausea and vomiting, heavy sensation in body, cold extremities, sleep disorders, white greasy coating, and slippery stringy pulse. Now it is mainly used for Menieres disease presenting the above-mentioned symptoms.