What is ark shell(Wa Leng Zi)?
From the standpoint of Chinese herbal medicine, it basically refers to the shells of arcidae species, in particular Arca subcrenata Lischke, Arca granosa Linnaeus, or Arca inflata Reeve. In China it is produced around the coastal areas and captured all year round for medicinal purpose. And the subsequent steps are to clean, slightly boil in boiling water, remove the meat, and finally dried in sun. Medicinally it is used broken and raw or calcined.
Arca subcrenata Lischke is slightly triangular or fan-shaped, 4 to 5cm long, and 3 to 4cm high. The outer shell is ridgy, with existing or off brown hair; the top is prominent and curled inward; from the top to the ventral side there are 30 to 34 shell radial ribs. Inner shell surface is smooth and white; the edge is with the depression corresponding to the ridge of the outer side. The hinge has a row of toothlets. It is hard, odorless, and tasteless. The shell contains large amounts of calcium carbonate and small amounts of calcium phosphate, magnesium, iron, silicates, sulfates, chlorides and organic matter. The total calcium accounts for more than 93% if calculated by calcium carbonate.
Ark shell health benefits
Modern pharmacology reveals that its ability of reducing gastric ulcer pain comes from calcium carbonate, which can neutralize stomach acid.
Ark shell, clam shells (Hai Ge Ke), and pumice (Fu Hai Shi) have quite similar medicinal uses in traditional Chinese medicine. However, it doesn’t mean that they are interchangeable. On the contrary, they need to be well distinguished clinically for proper uses.
All of the three are of salty in flavor and have the common function of eliminating phlegm, softening hardness and dissipating binds. As a result, all of them can be used to treat phlegm-fire stagnation induced scrofula, subcutaneous nodule, goiter and tumor; clam shell and pumice stone can also treat cough and asthma accompanied with thick yellow sputum that is caused by lung heat and phlegm-fire since both of them is capable of clearing lung and eliminating phlegm; clam shell and ark shell are also good at treating stomach discomfort and acid reflux since they can neutralize acidity and relieve pain.
And they do have their own advantage respectively on healing properties. Clam shell is still capable of inducing diuresis to alleviate edema. So it is often used for the treatment of edema and difficult urination; pumice stone can treat bloody stranguria and urolithiasis by inducing diuresis; ark shell removes blood stasis and disperses phlegm. Hence, it treats mass in the abdomen and Hepatosplenomegaly.