Oysters, also known as clams or oyster shells, are the shells of oysters such as the Jinjiang oyster, the Chang oyster, or the Dalian Bay oyster. They have a cool nature and a salty and bitter taste. They enter the liver and kidney meridians and have the functions of astringing yin, sinking yang, stopping sweating, astringing essence, transforming phlegm, and softening hardness. They are used to treat epilepsy, dizziness, spontaneous sweating, night sweats, nocturnal emission, cloudy urine, scrofula, goiter, and other conditions. They are commonly used in traditional Chinese medicine. There are counterfeit oysters on the market that use oyster-like animals from the same family as substitutes, so it is important to be careful when using them.
Genuine Oysters
1. Jinjiang oyster: The shell consists of two pieces, which are thick and round, oval, or triangular in shape. The left shell (lower shell) is attached to rocks and is larger and thicker, while the right shell (upper shell) is slightly flattened and smaller than the lower shell. The surface has very thin and straight yellow-brown or purple-brown scales that have accumulated over the years, forming layers as solid as stone, often with attached sea snails, moss, and other organisms. The shell can be gray, green, purple, brown, or other colors, with a white inner surface and gray-purple edges. The ligament is dark purple, and the adductor muscle scar is large and pale yellow, mostly oval or kidney-shaped, located on the mid-dorsal side. The foot is degenerated and does not have a byssus.
2. Chang oyster: The shell is larger and elongated, with a thick and parallel dorsal and ventral side. The length of the shell is generally three times greater than its height. The scales are arranged in a sparse wave-like pattern. The shell can be light purple, gray-white, or yellow-brown, with a white inner surface. The adductor muscle scar is horseshoe-shaped, brownish-yellow, located on the posterior dorsal side of the shell. The left shell is concave, and the scales are larger than those on the right shell.
3. Dalian Bay oyster: The shell is large, moderately thick, elongated from front to back, and gradually expands from the shell apex to the posterior, resembling a triangle. The left shell is attached, and the scales on the surface of the right shell form a wavy pattern, which is not as smooth as the Jinjiang oyster. The radial ribs are not obvious. The shell can be light yellow, and the inner surface is white. The adductor muscle scar can be white or purple and is located behind the back. These oysters have hard shells that are not easily broken, with a white layered cross-section. There is no odor, and the taste is slightly salty when consumed.
Counterfeit Zhe oyster
The shell is smaller, generally 3 to 6 centimeters long. The shape varies and can be irregularly oval or triangular. The shell is thin and fragile. The right shell is flat like a cover, with several concentric rings of scales on the surface and no radial ribs. The right shell is deeply concave, resembling a cap, with thick and robust radial ribs and fewer layers of scales. The shell can be light yellow with purple-brown or black stripes, and the inner surface is white with a slight luster. There is a faint odor and a slightly salty taste when consumed.
Modern pharmacological studies have shown that the main components of oysters are calcium carbonate, calcium phosphate, and calcium sulfate. They act as antacids and have stomach-soothing and analgesic effects. They are used to treat conditions such as excessive stomach acid, physical weakness, and night sweats. Although counterfeit Zhe oysters belong to the same family as genuine oysters, they do not possess the same medicinal properties, so they cannot be used as a substitute for genuine oysters.
