White conch shell, also known as white snail shell or ghost eyes. Recorded in the book "Emergency Prescriptions" by Zhang Zhongjing. It refers to the shell of the Bellamya quadrata (Benson) and other similar shells in the family Viviparidae. It can be collected all year round, and the shells that have turned white due to aging are collected, washed and dried.
【Processing Method】1. According to "Emergency Prescriptions": "Grind the white conch or white clam shell into powder..." In current practice, the original medicinal material is taken, washed, dried, and ground into small pieces.
2. According to "Medical Canon": "Remove the mud and sand from the white conch shell, then calcine it into fine powder." According to "Compendium of Materia Medica": "The white conch shell should be calcined to preserve its properties. Crush it, remove the internal dirt, and grind it into a very fine powder." According to "Danlao Fang": "Dry white conch shells that have been preserved for many years should be calcined and ground." In current practice, clean white conch shells are placed in a heat-resistant container, calcined until they turn red, then taken out to cool and ground into powder.
【Appearance of Herbal Pieces】White conch shell is irregularly shaped, with varying sizes. It may be curled inward or spiral-shaped. The outer surface is grayish-white or yellowish-white. Some may have ring-shaped ridges. The inner surface is relatively smooth, grayish-white or yellowish-white. It is hard in texture, with an uneven and keratinized appearance, grayish-white in color. It has a slight aroma and a mild taste. Calcined white conch shell is grayish-white or bluish-gray, brittle in texture, and white in color on the cross-section. It has a slight aroma and a slightly bitter taste.
【Processing Function】White conch shell has a sweet and mild nature and is neutral in temperature. It has the functions of resolving phlegm, dispersing masses, relieving pain, and promoting wound healing. It is used for hot phlegm cough, regurgitation, stomach pain, acid reflux, scrofula, and ulcers caused by burns. Raw white conch shell is used to resolve phlegm and disperse masses for cough and scrofula. For example, it can be used alone to treat sudden cough (as mentioned in "Emergency Prescriptions"), or to treat scrofula that has already burst (as mentioned in "Tanyeweng's Effective Formula"). Calcined white conch shell has a slightly warm nature. It is used to counteract acidity, relieve pain, and promote wound healing. It is used for stomach pain, acid reflux, and burns. For example, it is used in the formulation "White Jade Powder" for treating diaphragmatic pain (as mentioned in "Compendium of Materia Medica"). It can be used alone to treat damp phlegm causing heart pain (as mentioned in "Medical Canon"), or to treat various ulcers that do not heal (as mentioned in "Compendium of Materia Medica"), or to treat burns caused by boiling water (as mentioned in "Danlao Fang"). After calcination, the texture of the white conch shell becomes brittle, making it easy to crush and suitable for blending and formulation.
【Research on Processing】In the Jin Dynasty, it was recorded that the white conch shell should be ground into powder. In the Ming Dynasty, methods such as calcination and grinding were introduced. White conch shell mainly contains calcium carbonate. The composition of the raw product remains largely unchanged. After calcination, some of the calcium carbonate decomposes into calcium oxide, resulting in a brittle texture that is easy to grind.
