Oyster Shell (Mu Li)

Oyster Shell (mu li, 牡蛎), also known as Concha Ostreae, mainly refers to the shells of Ostrea gigas Thunberg, Ostrea talienwhanensis Crosse, or Ostrea rivularis Gould. The outer surface of the shells range from grayish-white to yellowish-purple in colour, with concentric scales that emanate from the back of the shell. The inner surface of the shells is usually white and smooth, though the edge may sometimes be purple. These Oyster Shells are in the family Ostreidae and are distributed along China’s coastal area. 

From at least 2000 BC, oysters have been cultivated in Japan and China. Oyster Shells have a long history of use in Traditional Chinese Medicine (TCM). In the west, Oyster Shells have not typically been used in Western herbology as a medicine but rather as an ingredient in love potions and other magical decoctions. In Mayan symbolism. Oyster shells were often used to depict the human ear. Oyster shells are often referred to in Mayan manuscripts as a reference to the “harvest of the sea”.

Oyster Shells can be collected all year round. After the removal of the flesh, keep the Oyster Shell, wash it clean and dry it under the sun. 

In Traditional Chinese Medicine (TCM), Oyster Shell falls under the category of ‘Herbs that anchor and calm the spirit’. Cold in nature, Oyster Shell can help individuals with too much Heat in their body, such as those experiencing a Yang Excess or a Yin Deficiency, to restore a harmonious yin-yang balance.

Salty in taste, Oyster Shell has a draining effect on the body by clearing accumulations, removing phlegm and softening hard lumps. In particular, the herb targets the bladder, the gallbladder, the Kidneys and the Liver.

Traditional Chinese Medicine (TCM) shows that Oyster Shell has the following health benefits.

Oyster Shell can pacify the Liver and subdue yang. By clearing Liver Heat and nourishing Liver yin, this herb can treat manifestations of yin deficiency with yang hyperactivity, such as dizziness, tinnitus and spasms in limbs. 

Oyster Shell can also soften hardness and dissipate nodulation. For phlegm nodules and scrofula caused by the Stagnation of Phlegm Fire, Oyster Shell can be combined with other phlegm-resolving, Heat-clearing, hardness-softening and nodulation-dissipating herbs to enhance its effectiveness. For mass caused by Qi Stagnation and Blood Stasis, Oyster Shell can be combined with other qi-moving and blood-activating herbs to enhance its effectiveness.

In addition, Oyster Shell can tranquilize the mind and treat symptoms such as restlessness, palpitations, anxiety or insomnia. By calming the mind, the herb can also help to manage stress.

With the ability to astringe and arrest discharge, Oyster Shell is indicated for syndromes of incontinence due to qi deficiency. For example, for spontaneous sweating, cold sweat and night sweat, Oyster Shell can be combined with other qi-nourishing, yin-nourishing or Fire-clearing herbs to reinforce its actions. For emission and spermatorrhea caused by Kidneys’ deficiency, Oyster Shell is often combined with Kidneys-tonifying and essence-securing herbs to enhance its effectiveness. 

Other than the above Oyster Shell benefits, the herb can absorb acidity and alleviate pain after being calcined. Oyster Shell can thus be indicated for symptoms such as acid reflux.

The recommended daily dosage of Oyster Shell is 15 – 30g, if smashed and consumed as a decoction. To astringe discharge, absorb acidity and alleviate pain, it is best to consume calcined Oyster Shell. To treat other conditions, you can use Oyster Shell in its unprocessed form.

Usually available in forms such as Oyster Shell powder and Oyster Shell capsules, Oyster Shell is also sometimes available as decoctions. These Oyster Shell products can be found in Asian markets, herbal shops and specialty stores.

Oyster Shell should not be used by individuals who are experiencing high fever without sweating, spermatorrhea caused by excess Cold, or allergic to shellfish.

Clinically, no adverse reactions on Oyster Shells have been reported. However, long-term usage or over-consumption of Oyster Shells may cause constipation and indigestion.

We strongly encourage you to consult your healthcare provider before deciding to add Oyster Shell to your healthcare routine.

Here is a summary for Oyster Shell (Mu Li):

• Herb name (Chinese): 牡蛎
• Herb name (Pin Yin): mǔ lì
• Herb name (English): Oyster Shell
• Herb name (Botanical): Concha Ostreae
• Origin of species: Ostrea gigas Thunberg; Ostrea talienwhanensis Crosse; Ostrea rivularis Gould
• Part(s) of herb used: Shell
• Geo-specific habitat(s): Along the coastal regions of China
• Taste(s) & Properties: Salty; Slightly cold; Administrates the Liver, Gall bladder and Kidney Meridians
• Actions: Calms the mind to help improve quality of sleep; Eases symptoms related to hypertension such as dizziness

Chang, C. C., & Huang, S. T. (2010). Is Traditional Chinese medicine effective for reducing hyperthyroidism?. The Journal of Alternative and Complementary Medicine, 16(11), 1217-1220. [Accessed on 29th January 2023]

Zhao, L., Zhao, A. G., Zhao, G., Xu, Y., Zhu, X. H., Cao, N. D., … & Xu, J. H. (2014). Survival benefit of traditional chinese herbal medicine (a herbal formula for invigorating spleen) in gastric cancer patients with peritoneal metastasis. Evidence-based Complementary and Alternative Medicine, 2014.[Accessed on 29th January 2023]