Ingredient Mineral (矿物 kuàng wù)

Shi Yan

Fossil Shell of Spirifer · 石燕

Cyrtiospirifer sinensis (Graban.) · Fossilia Cyrtiospiriferis

Also known as: Shi Yan Zi (石燕子, Stone Swallow), Da Shi Yan (大石燕, Large Stone Swallow), Yan Zi Shi (燕子石, Swallow Stone)

Shí Yàn is a fossil shell used in Chinese medicine to clear Damp-Heat from the lower burner and promote urination. It is often used for urinary tract infections, kidney stones, and vaginal discharge with heat signs. It can also be applied externally to help clear cloudiness and opacities from the eyes.

Category Stranguria-relieving diuretic herbs (利尿通淋药)
Therapeutic focus Urinary health Kidney health Eye health Women's health

TCM Properties

Temperature

Cool

Taste

Sweet (甘 gān), Salty (咸 xián)

Channels entered

Kidneys, Bladder

Parts used

Mineral (矿物 kuàng wù)

Educational content • Consult qualified TCM practitioners for diagnosis and treatment

What This Ingredient Does

Every ingredient has a specific set of actions — here's what Shi Yan does in the body, explained in both everyday and TCM terms

Therapeutic focus

In practical terms, Shi Yan is primarily used to support these areas of health:

Urinary health Kidney health Eye health Women's health

TCM Actions

In TCM terminology, these are the specific therapeutic actions that Shi Yan performs to restore balance in the body:

Clears Damp-Heat Promotes urination and relieves strangury Clears the eyes and reduces superficial visual obstructions Cools the Blood and stops bleeding

How these actions work

Shí Yàn's primary action is to clear Damp-Heat from the lower burner, making it effective for urinary tract infections, leukorrhea, and hemorrhoids with heat signs.

Its salty flavor and diuretic property promote urination and relieve strangury, helping to flush out stones and toxins.

When used topically, it can clear cloudiness and superficial opacities from the eyes (退目翳), often combined with other herbs for external application.

It also cools the Blood, stopping bleeding caused by Damp-Heat, such as blood in the urine or stool.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony. Shi Yan is used to help correct these specific patterns.

Why Shi Yan addresses this pattern

Shí Yàn's cool nature clears Heat, while its ability to promote urination drains Dampness from the Bladder. This directly resolves the root of Damp-Heat causing burning urination, frequency, and urgency.

A practitioner would look for one or more of these signs

Dysuria

Painful urination with burning sensation

Hematuria

Blood in urine due to Damp-Heat damaging blood vessels

Urinary Tract Infection

Frequent and urgent urination with dark, scanty urine

Commonly Used For

These are conditions where Shi Yan is frequently used — but only when they arise from the specific patterns it addresses, not in all cases

Arises from: Damp-Heat in the Bladder Damp-Heat in the Lower Burner

TCM Interpretation

In TCM, cystitis is typically diagnosed as Damp-Heat invading the Bladder, leading to symptoms of burning urination, frequency, and urgency. The Heat causes inflammation and pain, while Dampness creates the feeling of heaviness and murky urine.

Why Shi Yan Helps

Shí Yàn's cool energy directly counteracts the Heat, while its diuretic action dispels Dampness through urine. It specifically targets the Bladder channel, so it reaches the site of infection quickly, relieving symptoms and clearing the pathogen.

Also commonly used for

Hemorrhoids

Cools the Blood and resolves Damp-Heat in the lower burner to stop bleeding and swelling.

Vitreous Opacity

Applied topically to clear corneal opacity and improve vision.

Ingredient Properties

Every ingredient has an inherent temperature, taste, and affinity for specific channels — these properties determine how it interacts with the body

Temperature

Cool

Taste

Sweet (甘 gān), Salty (咸 xián)

Channels Entered

Kidneys Bladder

Parts Used

Mineral (矿物 kuàng wù)

Dosage & Preparation

These are general dosage guidelines for Shi Yan — always follow your practitioner's recommendation, as dosages vary based on the formula and your individual condition

Standard dosage

3–9g

Maximum dosage

不超过9g；磨汁服用时单次1.5–3g。过量可能引起胃肠不适。

Dosage notes

煎汤用3–9g；磨汁或水飞粉吞服0.5–3g。外用点眼可水磨取汁。治疗湿热淋证、带下时用中等剂量；用于退目翳或慢性肠风痔漏时可减少剂量，持续服用。

Preparation

入煎剂前宜捣碎或打碎，可先煎20–30分钟带动药性。研末冲服或水飞后外用更为便捷；点眼时以水研磨取上层清液使用。醋淬品可直接研细入药。

Processing Methods

In TCM, the same ingredient can be prepared in different ways to change its effects — here's how processing alters what Shi Yan does

Processing method

取原药材，洗净，干燥，捣碎或碾磨成细粉（生用）。

How it changes properties

保持其甘、咸、凉之性，专于清热利湿、通淋止带，无煅制带来的温涩之变。

When to use this form

用于急性湿热淋证、小便不利、带下，亦可用于磨水点眼退翳。

Common Ingredient Pairs

These ingredients are traditionally combined with Shi Yan for enhanced therapeutic effect

Hua Shi
Hua Shi 1:1 to 1:2

Shí Yàn clears Damp-Heat and promotes urination; Huá Shí facilitates urination especially for painful strangury. Together they powerfully expel Damp-Heat from the lower burner, used for acute cystitis and urinary stones.

When to use: For Damp-Heat strangury with burning pain, turbid urine, and urinary obstruction.

Qu Mai
Qu Mai 1:1

Both herbs drain Damp-Heat and promote urination to relieve strangury; Shí Yàn adds the ability to cool Blood and stop bleeding, while Qú Mài specifically targets blood strangury.

When to use: For strangury with hematuria or painful urination due to Damp-Heat.

Dong Kui Zi
Dong Kui Zi 1:1

Shí Yàn clears Damp-Heat and promotes urination; Dōng Kuí Zǐ is a mild diuretic that also moistens the intestines. Together they gently soothe the urinary tract and promote stone passage.

When to use: For chronic Damp-Heat with urinary difficulty and mild stone discomfort, or when constipation accompanies.

Comparable Ingredients

These ingredients have overlapping uses — here's how to tell them apart

Hua Shi
Shi Yan vs Hua Shi

Both clear Damp-Heat and promote urination, but Shí Yàn also cools the Blood to stop bleeding and removes superficial visual obstructions, while Huá Shí is slightly milder and specifically treats painful strangury.

Dong Kui Zi
Shi Yan vs Dong Kui Zi

Shí Yàn's salty taste softens hardness and clears Heat from the Blood, making it useful for stones and bleeding; Dōng Kuí Zǐ has a moistening effect that can relieve constipation and soothe the urinary tract.

Identity & Adulterants

Related species and common adulterations to be aware of when sourcing Shi Yan

历史上常与“禽类石燕”（钟乳洞中似蝙蝠的动物）相混淆，后者被视为助阳药，功效截然不同。此外，不同种属的腕足动物化石（如相近种类）有时充作石燕，但正品应为中华弓石燕（Cyrtiospirifer sinensis）的化石。

Educational content — always consult a qualified healthcare provider or TCM practitioner before using any ingredient.

Toxicity Classification

Classical Chinese pharmacopoeia toxicity rating for Shi Yan

Non-toxic

本品主要成分为碳酸钙，无毒。但过量服用可能导致钙摄入过多，引起轻度便秘或胃部不适。经火煅醋淬后质地变酥，更易吸收。不宜长期大量服用。

Contraindications

Situations where Shi Yan should not be used or requires extra caution

Caution

Pregnancy — traditionally considered contraindicated (孕妇慎服/忌服). Use only under strict practitioner guidance if absolutely necessary.

Caution

Body deficiency with no damp-heat signs — its draining action may further weaken the constitution.

Special Populations

Important considerations for pregnancy, breastfeeding, and pediatric use

Pregnancy

传统文献记载孕妇慎服或忌服。石燕具有清热利湿、通利下行之性，可能扰动胎气。无现代安全数据，孕妇应避免使用，除非在执业中医师严格指导下权衡利弊后使用。

Breastfeeding

尚无哺乳期安全性数据，建议慎用。

Children

可用于小儿疳积、淋证等，用量应酌减，一般1.5–3g，且需在医师指导下使用。传统有石燕丸等儿科专门制剂（如绿豆大小，每服7丸，葱白汤下）。

Drug Interactions

If you are taking pharmaceutical medications, be aware of these potential interactions with Shi Yan

因含有大量碳酸钙，若与四环素类抗生素、双膦酸盐类药物、左甲状腺素等同时服用，可能影响吸收，建议间隔至少2小时。

Dietary Advice

Foods and dietary considerations when taking Shi Yan

服用期间忌食生冷、油腻及辛辣食物，以免加重湿热。

Sourcing & Harvesting

Where Shi Yan is sourced, when it's harvested or collected, and how to assess quality

Primary growing regions

湖南、广西、四川、山西、江西；尤其以湖南祁阳、零陵（今永州）所产为道地药材。

Quality indicators

以状如蚶、色青黑、质坚硬无杂石者为佳。断面土黄色或青白色，对光照之具闪星样光泽。气微，味淡。煅制品应为灰白色细腻粉末，醋淬品略带醋气。

Classical Texts

Key passages from the classical Chinese medical texts that describe Shi Yan and its therapeutic uses

《唐本草》: “以水煮汁饮之，主淋有效。” (Boil in water and drink the juice, effective for strangury.)

《本草纲目》: “石燕性凉，乃利窍行湿热之物。” (Fossil Stone Swallow is cool in nature, an agent that opens the orifices and drains damp-heat.)

《玉楸药解》: “利水通经，止带，催生。治淋沥热涩，尿血便秘，消渴，带下，痔漏。” (Promotes urination and menstruation, stops leukorrhea, and hastens delivery. Treats painful urinary dribbling, blood in urine, constipation, thirsting, leukorrhea, and hemorrhoids.)

Historical Context

The history and evolution of Shi Yan's use in Chinese medicine over the centuries

石燕之名源自其外形似燕子。早在晋代顾恺之《启蒙记》中记载“零陵郡有石燕，得风雨则飞如真燕”，北魏郦道元《水经注》亦沿用此说，使石燕蒙上神秘色彩。唐代《新修本草》首次指出其仅为化石，不可飞翔。宋代学者实地观察，揭示其坠落为岩石热胀冷缩所致，但其“遇风雨群飞”的传说仍流传甚广。

明代李时珍在《本草纲目》中进一步明确石燕分两类——一为石类腕足动物化石，即今日药用石燕；另一为钟乳洞中形似蝙蝠的禽类，食之可助阳。世俗常将二者混淆，误认石类石燕为助阳之品，李时珍纠正其谬。这一区分不仅厘清了药性，也体现了本草学从神话到实证的演变。现代地质学确认其为古生代腕足动物中华弓石燕的壳体化石，主含碳酸钙，无毒，以清热利湿、通淋止带为要。