Herbs & Botanicals

What is clam shell? What is it used for?

Clam shells come from the clam, a type of shellfish found in rivers, lakes and marshes. In China, the two most commonly used clam shells in traditional Chinese medicine come from the triangular sail clam (hyriopsis cumingii L.) and the wrinkled crown clam (cristaria plicata L.).

Clam shells are harvested year round. They are typically boiled in water, then dried in the sun. They can be used either raw, or after being calcined (heated at a high temperature), and are pounded or ground into powder.

In traditional Chinese medicine, clam shells have salty and cold properties, and are associated with the Kidney, Lung and Stomach meridians. The main functions of clam shell are to clear heat in the lungs, resolve phlegm, soften hardness, and release nodules. It helps to clear up congestion and accumulations of sputum in the chest, along with goiters, asthma and angina. Clam shell is often consumed with other herbs, such as mulberry bark, trichosanthes and ark shell.

How much clam shell should I take?

The typical dose of clam shell is between 6 and 15 grams, taken with water as a decoction. Clam shell should be pounded into a fine powder and placed in a cloth bag before being poured into water. If being poured directly into the water, clam shell should be removed with a strainer before drinking the decoction.

What forms of clam shell are available?

In addition to most rivers, lake beds and sea shores, whole, cleaned clam shells can be found at many Asian markets and specialty stores. Powdered clam shell is available at some herbal shops and markets.

What can happen if I take too much clam shell? Are there any interactions I should be aware of? What precautions should I take?

As of this writing, there are no known drug interactions or side-effects associated with clam shell. As always, make sure to consult a licensed health care provider before taking clam shell or any other herbal remedy or dietary supplement.

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References

• College of Traditional Chinese Medicine Practitioners and Acupuncturists of British Columbia. Core Competencies of TCM Practitioners in British Columbia. Published March 2002.
• Concha cyclinae. Available online.
• Flaws B. Ye Tian-shi's commonly used medicinal combinations. Available at www.bluepoppy.com/press/download/articles/ye-herb.cfm.
• Hai ge ke. Available online.
• Hai ge ke. Available online.