Pinellia, Ban Xia 半夏
Prepared Pinellia, Zhi Ban Xia 制半夏

Dose:

Only the prepared product should be used internally.
Decoction: 3–9 grams
Powder: 500mg–2 grams

Preparation:

A number of different preparations are used. Only prepared Pinellia Ban Xia is used internally, and is obtained that way on the Chinese medicine market. The primary methods of processing used today combine either Alum and Ginger, or Lime and Licorice.

1. Raw (unprocessed) Pinellia (Sheng Ban Xia):
  Toxic, only used externally for swelling and pain.
  Traditionally, raw Pinellia was sometimes decocted after soaking well without further preparation. In this case it is boiled for an extended period of time (2 hours), as in the case of Aconite. This is generally no longer done.
2. Traditional Processed Pinellia
  The raw tubers were rinsed well in water 7–10 times to remove irritants. Then they were sun-dried.
  While this does reduce irritant effects, later generations created better methods of preparation as shown below.
3. Alum-processed Pinellia (Qing Ban Xia):
  Purified by being soaked and boiled, or soaked in Alum solution to remove toxicity. It is drying and used for Damp and Cold-Phlegm.
4. Prepared Pinellia (Fa Ban Xia):
  Raw Ban Xia rhizome (100 parts) is soaked to reduce the numbing sensation, then it is soaked in a decoction of Lime (10 parts) and Licorice (15 parts) until the center becomes yellow and the rhizome is semi-transparent and horn-like. This is the standard product available in the west.
5. Ginger Pinellia (Jiang Ban Xia):
  The rhizome is soaked as before; then it is boiled with fresh Ginger and Alum until cooked through. This is more warming, more drying, and better for Cold-Phlegm.
6. Lime-processed Pinellia; 
  Processed with Lime powder after it has been soaked and boiled.
7. Bamboo juice Pinellia (Zhu Li Ban Xia):
  Raw or processed Pinellia Ban Xia is soaked in Bamboo juice and dried. This reduces its heat and makes it effective for Phlegm-Heat Cough, Vomiting due to Stomach Phlegm-Heat and Phlegm-Heat blocking internally.
9. There are several other traditional variations of preparation.

Ban Xia Qu (fermented leaven of Ban Xia):

Ban Xia Qu is a medicated Leaven prepared from Pinellia Ban Xia. It is a way to prepare Ban Xia to reduce its toxicity, while simultaneously making it stronger to resolve Phlegm and Damp.
There are 2 primary types of preparation, a Traditional, and a Modern (although there are many variations):
1. Ginger-Alum Stream (Han Shi Yi Tong Tradition)
Qing Ban Xia (Pre-soaked, semi-processed Pinellia powder): 100 parts
Wheat Flour (Mian Fen): 10 parts
Wheat Bran (Sheng Fu Pi): 10 parts
Fresh Ginger Juice (Sheng Jiang Zhi): 12.5 parts
White Alum (Bai Fan / Potassium Alum): 6 parts
Shen Qu (Standard Medicated Leaven powder): 3 parts
Dissolve the crystalline White Alum in a small amount of warm water, then filter it and mix it directly into the freshly squeezed Ginger juice.
Thoroughly blend the dry Qing Ban Xia powder, wheat flour, bran, and Shen Qu powder together. Next, Pour the Ginger-Alum liquid into the dry powder matrix. Knead firmly until it forms a uniform, semi-dry dough texture. Press the dough flat into rectangular cakes or small 1-inch cubes. Wrap the cakes in fresh Broussonetia leaves (Chu Ye) or damp cloth. Incubate in a dark, warm, humid environment (typically 30–35°C) until white mycelium (fungal mold) fully and evenly coats the surface. Then remove the cakes and sun-dry or bake at low heat until entirely dehydrated and crisp
2. Multi-Herbal Stream (Modern Production/Pharmacopoeia
Fa Ban Xia (Processed Pinellia powder): 100 kg
Wheat Flour: 400 kg
Chi Xiao Dou (Vigna umbellata): 30 kg
Ku Xing Ren (Bitter Apricot Seed): 30 kg
Fresh Qing Hao (Artemisia annua): 30 kg
Fresh La Liao (Polygonum hydropiper): 30 kg
Fresh Cang Er Cao (Xanthium sibiricum): 30 kg
Boil the fresh Qing Hao, La Liao, and Cang Er Cao together in a large vat of water to create a highly concentrated, dark green herbal extraction liquid. Strain. Then boil the Chi Xiao Dou until soft, crush them, and grind the Ku Xing Ren seeds down into a uniform oily flour.
Combine the Fa Ban Xia powder, wheat flour, seed powders, and starches. Add the warm herbal extraction juice gradually, mixing until a dough is formed. Press the dense paste into shallow molds and cut into standard 25-gram cubes. Pack them in insulated, straw-lined fermentation rooms for 3 to 5 days, tracking the relative humidity to ensure proper mold growth. Once the cubes take on a pale-yellow hue and display fine, porous honeycomb structures internally (Xi Feng Wo Yan), they are fully sun-dried