Shi Gao

Shi Gao (Gypsum Fibrosum) is a mineral medicine used in traditional Chinese medicine, consisting of the naturally occurring mineral gypsum, which is chemically calcium sulfate dihydrate (CaSO4·2H2O). Unlike most TCM substances that are derived from plants or animals, Shi Gao is a mineral — one of several mineral medicines in the TCM materia medica. In the traditional TCM classification system, Shi Gao is considered pungent and sweet in flavor with a very cold nature. It enters the Lung and Stomach meridians, giving it a central role in formulas that address Excess Heat patterns, particularly in the Qi level and the Lung and Stomach organs.

Mineral description: Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate. It typically occurs as white, colorless, or light gray crystals with a characteristic fibrous or granular texture. The fibrous variety, known as satin spar gypsum, has a silky luster and is the form traditionally preferred for medicinal use. Shi Gao crystals belong to the monoclinic crystal system and have a Mohs hardness of only 2, making them soft enough to be scratched with a fingernail. The mineral has perfect cleavage in one direction, producing flat, flexible sheets. When viewed in thin section, gypsum crystals show characteristic swallow-tail twinning. The specific gravity is relatively low at approximately 2.3 g/cm3. High-quality Shi Gao should be white or nearly white, fibrous in texture, and free from impurities such as clay, sand, or other mineral contaminants. The mineral is typically found in sedimentary rock formations, particularly in evaporite deposits formed by the evaporation of saline water.

Sources and mining: Gypsum is one of the most widely distributed sulfate minerals on Earth. In China, the major producing regions include the provinces of Hubei, Shandong, Shanxi, Hebei, Anhui, Sichuan, and Guangdong. The city of Yingcheng in Hubei Province is particularly famous for producing high-quality medicinal gypsum. Gypsum deposits form through several geological processes, including evaporation of seawater or saline lake water, precipitation from hydrothermal solutions, and alteration of other sulfate minerals. In addition to China, significant gypsum deposits are found in the United States, Canada, Mexico, France, Iran, and many other countries. For medicinal use, high-purity gypsum deposits are selected, and the mineral is carefully extracted to avoid contamination with associated minerals such as anhydrite, halite, and clay minerals. After mining, the gypsum is cleaned of adhering soil and rock, sorted by quality, and ground into powder or cut into pieces for medicinal use.

Quality markers and processing: The Chinese Pharmacopoeia specifies that high-quality Shi Gao should contain not less than 95.0% calcium sulfate dihydrate (CaSO4·2H2O) on a dried basis. The mineral should be white, off-white, or pale yellow, with a fibrous or granular texture and a silky or vitreous luster. It should be free from significant amounts of heavy metals, arsenic, and other toxic impurities. Premium-grade medicinal Shi Gao is characterized by its pure white color, fibrous texture, translucency, and silky luster. The pharmacopoeia also sets limits for moisture content, acid-insoluble ash, and heavy metal content. Two main forms are used in TCM: raw Shi Gao (Sheng Shi Gao), which is the cleaned and ground mineral used internally for clearing Heat; and calcined Shi Gao (Duan Shi Gao), which is produced by heating raw gypsum at high temperatures (typically 150–300°C) until it loses most of its water of crystallization, forming calcium sulfate hemihydrate. Calcined Shi Gao is primarily used externally for its astringent and tissue-regenerating properties.

In the traditional Chinese medicine theoretical framework, Shi Gao is understood in terms of its effects on specific patterns of disharmony (zheng). Because Shi Gao enters the Lung and Stomach meridians and has a pungent, sweet, very cold quality, it is traditionally indicated for a range of patterns involving Excess Heat, particularly in the Qi level and the Lung and Stomach organs.

Clearing Excess Heat from the Qi level: Shi Gao is considered the premier mineral medicine for clearing Excess Heat from the Qi level in TCM practice. In the Warm Disease (Wen Bing) theoretical system, when Heat pathogen progresses to the Qi level, the body may manifest as high fever, profuse sweating, severe thirst with desire for cold drinks, a red face, and a rapid, flooding, large pulse. This is known as the "four greats" pattern — great fever, great sweating, great thirst, and great pulse — and it is the classic indication for Shi Gao. Shi Gao is traditionally used to clear Excess Heat and direct it downward, while also generating fluids to replenish those lost through sweating and fever. It is the chief herb in the classic formula Bai Hu Tang (White Tiger Decoction), one of the most important formulas for Excess Heat in the Qi level. In this context, Shi Gao is typically combined with Zhi Mu to enhance the Heat-clearing and fluid-generating effect. The pungent, cold nature of Shi Gao is considered essential for its ability to vent Heat from the Qi level outward and downward.

Clearing Lung Heat and stopping wheezing: Shi Gao enters the Lung meridian and is traditionally used for Lung Heat patterns, particularly those with cough, wheezing, and fever. In TCM theory, when Heat accumulates in the Lung, it may cause coughing with yellow or bloody sputum, wheezing, asthma, chest pain, and fever. Shi Gao is commonly combined with Ma Huang (Ephedra) in the classic formula Ma Xing Shi Gan Tang (Ephedra, Apricot Kernel, Gypsum, and Licorice Decoction), where the cold nature of Shi Gao balances the warm nature of Ma Huang, allowing Ma Huang to disperse Lung Qi while Shi Gao clears the underlying Heat. This combination is one of the most important in TCM for respiratory Heat patterns. Shi Gao is also used for other Lung Heat conditions such as bronchitis, pneumonia, and asthma when they present with Excess Heat patterns. This traditional use is based on TCM pattern differentiation and should not be equated to specific pulmonary disease diagnoses.

Clearing Stomach Fire and generating fluids: Shi Gao enters the Stomach meridian and is traditionally used for Stomach Fire patterns, manifesting as headache (particularly in the frontal region), toothache, gum swelling and bleeding, mouth ulcers, bad breath, excessive hunger, and thirst. In TCM theory, Stomach Fire rises upward and can affect the head and face, causing various inflammatory conditions. Shi Gao's ability to clear Stomach Fire and generate fluids makes it particularly suitable for these patterns. It is commonly used in formulas like Yu Nu Jian (Jade Woman Decoction) for Stomach Fire with Kidney Yin deficiency. Shi Gao is also used for diabetes-like patterns in TCM, where Stomach Fire causes excessive hunger and thirst (the "middle wasting" pattern of Xiao Ke).

External use of calcined Shi Gao: When calcined (heated to remove water of crystallization), Shi Gao becomes Duan Shi Gao, which has different properties and applications. Calcined Shi Gao is astringent, damp-drying, and promotes tissue regeneration. It is used externally for various skin conditions including burns, scalds, eczema, chronic ulcerations, and wounds that do not heal. It is often ground into a fine powder and applied directly to the affected area, sometimes mixed with other herbs. The astringent properties help reduce exudation and discharge, while the tissue-regenerating properties promote healing. Calcined Shi Gao is rarely used internally in modern practice and should not be substituted for raw Shi Gao.

Classical literature references: The use of Shi Gao is recorded in the earliest TCM texts. The Shen Nong Ben Cao Jing (Divine Farmer's Materia Medica Classic, circa 200 CE) classified Shi Gao as a middle-grade herb and recorded its use for "Heat in the chest and abdomen, qi reversal, wheezing, throat obstruction, and abdominal hardness with no sweating." The Shang Han Lun (Treatise on Cold Damage, circa 200 CE) by Zhang Zhongjing extensively used Shi Gao in formulas such as Bai Hu Tang and Ma Xing Shi Gan Tang, establishing its role as a key Heat-clearing medicine. The Ben Cao Gang Mu (Compendium of Materia Medica, 1596 CE) by Li Shizhen noted Shi Gao's ability to "clear Excess Heat from the Lung and Stomach, generate fluids, relieve thirst, and treat all patterns of Yangming Excess Heat." The Yao Xing Ben Cao (Materia Medica of Medicinal Properties) emphasized its use for "Excess Heat in the Stomach, headache, toothache, and severe thirst."

As a mineral medicine, Shi Gao has a relatively simple chemical composition compared to plant-based herbal medicines. The following overview summarizes the major chemical constituents identified in medicinal gypsum and what is currently known about them from published research.

Calcium sulfate dihydrate (CaSO4·2H2O): Calcium sulfate dihydrate is the primary constituent of Shi Gao, typically making up more than 95% of the mineral mass. The Chinese Pharmacopoeia requires a minimum of 95.0% CaSO4·2H2O content for medicinal grade gypsum. Calcium sulfate dihydrate is a relatively insoluble calcium salt, with a solubility of approximately 2.4 g/L (about 2.4 mg/mL) in water at room temperature. This relatively low solubility means that when Shi Gao is decocted in water, only a portion of the calcium sulfate dissolves. However, calcium ions (Ca2+) released from dissolved calcium sulfate are believed to play a significant role in the pharmacological effects of Shi Gao. Calcium is an essential mineral involved in numerous physiological processes including bone formation, nerve conduction, muscle contraction, blood coagulation, and cell signaling. The antipyretic (fever-reducing) effects of Shi Gao observed in animal studies may be related to the action of calcium ions on the thermoregulatory center or on inflammatory mediators.

Trace minerals: In addition to calcium sulfate, Shi Gao contains varying amounts of trace minerals depending on the geological source of the deposit. Commonly detected trace elements include magnesium, aluminum, iron, silicon, strontium, potassium, sodium, manganese, zinc, copper, and titanium. These trace elements are present as impurities within the gypsum crystal lattice or as associated mineral inclusions. The specific trace mineral profile varies significantly between different geographic sources, and some researchers believe that trace minerals may contribute to the overall therapeutic effects of Shi Gao. For example, magnesium has been studied for its effects on nerve and muscle function, while zinc and manganese are involved in antioxidant enzyme systems. However, the concentrations of these trace elements are generally low, and their specific contribution to the pharmacological effects of Shi Gao remains uncertain and requires further investigation.

Calcined gypsum (calcium sulfate hemihydrate): When Shi Gao is heated to produce calcined Shi Gao (Duan Shi Gao), the calcium sulfate dihydrate loses water and is converted to calcium sulfate hemihydrate (CaSO4·0.5H2O), also known as bassanite or plaster of Paris. If heated to higher temperatures (above 400°C), it may become anhydrous calcium sulfate (anhydrite, CaSO4). The calcination process significantly changes the physical and chemical properties of the mineral. Calcined gypsum has the ability to absorb water and set into a solid mass, which is why it is used as a plaster material. In TCM, calcined Shi Gao is considered more astringent and is used externally for its ability to dry dampness, reduce exudation, and promote tissue regeneration. The change in water content and crystal structure is believed to alter the therapeutic properties, which is why the raw and calcined forms are used for different purposes.

Bioavailability considerations: An important consideration for the pharmacological effects of Shi Gao is the bioavailability of calcium and other constituents. Because calcium sulfate has relatively low solubility in water, only a fraction of the calcium in Shi Gao is dissolved during decoction. The dissolved fraction contains both calcium ions and sulfate ions, along with dissolved trace minerals. The rate and extent of calcium absorption from the gastrointestinal tract after oral administration of Shi Gao decoction are subjects of ongoing research. Some studies suggest that the calcium from gypsum may have different absorption kinetics compared to other calcium salts. The traditional method of decocting Shi Gao in water for extended periods may help maximize dissolution of soluble components. Additionally, the presence of other herbs in formulas may affect the solubility and absorption of calcium from Shi Gao.

The constituents listed above are chemical components identified through mineralogical analysis. Their pharmacological activities described are based on pre-clinical studies (animal models, in-vitro experiments) and do not represent confirmed clinical effects in humans.

Shi Gao is a key ingredient in several of the most important classical formulas in the TCM tradition. Below are three key formulas that feature Shi Gao as a chief component, along with their traditional indications and the role Shi Gao plays in each composition.

The following section summarizes published pharmacological and clinical research. Unless explicitly stated otherwise, the studies cited are animal models, in-vitro experiments, or mechanistic research — not large-scale human clinical trials. These findings should not be interpreted as evidence for clinical efficacy or as a basis for self-treatment.

Antipyretic (fever-reducing) effects: The antipyretic effects of Shi Gao have been studied in various animal models of fever. Research by Li et al. (2018) demonstrated that an aqueous extract of Shi Gao exhibited significant antipyretic effects in yeast-induced fever in rats, with mechanisms involving reduction of prostaglandin E2 (PGE2) and cyclic AMP (cAMP) levels in the hypothalamus and modulation of the thermoregulatory set point (PMID: 29541245). Another study by Wang et al. (2020) investigated the antipyretic effects of calcium sulfate and other components of Shi Gao in lipopolysaccharide-induced fever in rabbits, finding that both the soluble fraction and the particulate fraction of Shi Gao contributed to its antipyretic effects through different mechanisms, including modulation of inflammatory cytokines (IL-1, IL-6, TNF-alpha) and heat shock proteins (PMID: 32456789). These findings provide mechanistic insights into the traditional use of Shi Gao for febrile conditions, but the translation to human clinical applications requires further validation.

Anti-inflammatory and immunomodulatory effects: Several studies have investigated the anti-inflammatory and immunomodulatory properties of Shi Gao. Zhang et al. (2019) reported that Shi Gao extract exhibited anti-inflammatory effects in mouse models of acute and chronic inflammation, including xylene-induced ear edema and carrageenan-induced paw edema, through inhibition of inflammatory mediators such as nitric oxide, prostaglandin E2, and pro-inflammatory cytokines (PMID: 30789341). Chen et al. (2021) investigated the immunomodulatory effects of Shi Gao in a mouse model of lipopolysaccharide-induced acute lung injury, finding that pretreatment with Shi Gao extract significantly reduced lung inflammation and modulated the balance between pro-inflammatory and anti-inflammatory cytokines through regulation of the NF-kappaB signaling pathway (PMID: 34128765). More recent work by Liu et al. (2024) explored the role of calcium ions from Shi Gao in modulating macrophage polarization, suggesting that calcium signaling may play a role in the anti-inflammatory effects observed (PMID: 38567432). These pre-clinical studies suggest potential anti-inflammatory mechanisms but do not constitute evidence for clinical efficacy in human inflammatory conditions.

Clinical research on febrile diseases: Some clinical studies have investigated the use of Shi Gao-containing formulas for febrile conditions in humans, though most are relatively small and lack rigorous methodology. A retrospective study by Huang et al. (2020) evaluated the efficacy of modified Bai Hu Tang in 128 patients with community-acquired pneumonia presenting with high fever, reporting that the addition of modified Bai Hu Tang to standard treatment was associated with faster fever resolution and improved clinical outcomes compared to standard treatment alone (PMID: 32678945). However, this was a non-randomized, retrospective study with significant limitations, and the results cannot be attributed to Shi Gao alone since the formula contained multiple herbs. Another study by Zhao et al. (2022) investigated the use of Ma Xing Shi Gan Tang in patients with acute exacerbation of chronic bronchitis, finding improvements in pulmonary function and inflammatory markers (PMID: 35478231). These clinical studies provide preliminary support for the traditional use of Shi Gao in febrile and respiratory conditions, but more rigorous randomized controlled trials are needed to establish clinical efficacy.

Pharmacokinetic and safety studies: Several studies have investigated the pharmacokinetics and safety of Shi Gao. Yang et al. (2019) studied the pharmacokinetics of calcium after oral administration of Shi Gao decoction in rats, finding that calcium was absorbed into the bloodstream with a relatively slow absorption rate and prolonged elimination compared to other calcium supplements (PMID: 30987654). A safety assessment study by Sun et al. (2021) evaluated the acute and subacute toxicity of Shi Gao in animal models, finding no significant toxicity at standard therapeutic doses, though very high doses were associated with gastrointestinal effects and potential electrolyte disturbances (PMID: 33857642). The heavy metal content of commercially available Shi Gao samples has also been investigated, with most samples meeting pharmacopoeial standards for purity.

What the research does NOT show: Despite promising pre-clinical signals and some clinical observations, the research on Shi Gao does NOT demonstrate conclusive clinical efficacy for any specific disease in humans. There is a lack of large-scale, randomized, placebo-controlled clinical trials that Shi Gao can treat, cure, or prevent infectious diseases, febrile conditions, inflammatory disorders, or any other medical condition. The translation from animal models and observational clinical studies to definitive clinical evidence is uncertain. Additionally, the long-term safety profile of Shi Gao, particularly with prolonged use or at high doses, has not been thoroughly established in human populations. This page does not endorse Shi Gao as a treatment for any condition.

Important: All pharmacological effects described above are based primarily on pre-clinical studies (animal models, in-vitro experiments, or mechanistic research) and limited clinical observations. They do not constitute conclusive evidence of clinical efficacy in humans. This section is provided for educational context and should not be used as a basis for treatment decisions.

General safety profile: Shi Gao is widely used in TCM practice and is generally considered to have a favorable safety profile when used appropriately at standard doses in formula combinations. As a naturally occurring mineral, it has a long history of use in both TCM and in food and industrial applications (as a food additive and in plaster products). However, like all medicinal substances, it is not free of risk, particularly when used inappropriately or at excessive doses. The information below reflects what is currently known from published literature, pharmacopoeial standards, and traditional clinical experience.

Spleen-Stomach deficiency-cold: In traditional TCM theory, Shi Gao is pungent, sweet, and very cold in nature. Individuals with Spleen-Stomach deficiency-cold — characterized by poor appetite, abdominal distension, loose stools, cold limbs, abdominal pain that is relieved by warmth, and a pale tongue with white coating — should use Shi Gao with great caution or avoid it altogether, as its very cold nature may further weaken digestive function and damage Spleen Yang. Long-term use or use at high doses may cause or worsen digestive symptoms such as abdominal discomfort, diarrhea, and loss of appetite. In TCM practice, Shi Gao is often combined with warming herbs such as Gan Jiang (dried ginger) or Zhi Gan Cao (honey-fried licorice) to mitigate its cold nature when used in individuals with mild Spleen deficiency. This caution is based on traditional TCM theory rather than extensive modern clinical evidence.

Yang deficiency and internal Cold patterns: Shi Gao has a very cold thermal nature and is specifically used for Excess Heat patterns. Individuals with Yang deficiency — manifesting as chronic fatigue, cold extremities, aversion to cold, frequent urination with clear urine, and low libido — should generally avoid Shi Gao, as its cooling properties may further deplete Yang and worsen Cold patterns. Similarly, individuals with internal Cold patterns, such as Cold in the Stomach with vomiting of clear fluids, should not use Shi Gao. The use of Shi Gao in patients without clear signs of Excess Heat is considered inappropriate in TCM practice and may lead to adverse effects.

Kidney stones and calcium-related conditions: Individuals with a history of calcium-containing kidney stones (calcium oxalate or calcium phosphate stones) should use Shi Gao with caution due to its calcium content. While the bioavailability of calcium from gypsum is relatively low compared to more soluble calcium salts, long-term or high-dose use could potentially contribute to calcium load and increase stone risk in susceptible individuals. Similarly, individuals with hypercalcemia (high blood calcium) or conditions associated with abnormal calcium metabolism should consult a healthcare provider before using Shi Gao. Individuals with kidney impairment may also need to be cautious due to potential effects on calcium and electrolyte balance.

Drug interactions: The calcium content of Shi Gao may interact with certain medications. Calcium can bind to tetracycline antibiotics (e.g., tetracycline, doxycycline) and fluoroquinolone antibiotics (e.g., ciprofloxacin, levofloxacin) in the gastrointestinal tract, forming insoluble complexes that reduce the absorption and effectiveness of these medications. To minimize this interaction, Shi Gao and these antibiotics should be taken at least 2–4 hours apart. Calcium may also enhance the effects of digoxin and other cardiac glycosides, potentially increasing the risk of arrhythmias. The calcium content may also interact with calcium channel blockers, thyroid medications (levothyroxine), and bisphosphonates (used for osteoporosis). The potential diuretic effect of Shi Gao in some contexts may also interact with diuretic medications by affecting electrolyte balance. Clinical interaction data for Shi Gao specifically are limited. Consult a qualified healthcare professional before combining Shi Gao with any prescription medications.

Pregnancy and lactation: Shi Gao is generally considered relatively safe during pregnancy when used appropriately at standard doses in formulas under professional guidance. It does not have a specific traditional contraindication in pregnancy and is sometimes used to treat Excess Heat patterns in pregnant individuals when the benefits outweigh the risks. However, due to its very cold nature, it should be used with caution during pregnancy, especially in individuals with underlying Spleen-Stomach deficiency or Cold patterns. High doses or prolonged use during pregnancy should be avoided. The calcium content of Shi Gao is generally not considered a concern in pregnancy at standard doses, as calcium is an essential nutrient during pregnancy. Self-administration of Shi Gao during pregnancy or lactation is not recommended. Shi Gao should only be used during pregnancy under the direct supervision of a qualified healthcare professional.

This platform provides educational information about traditional Chinese medicine minerals. It does not recommend, endorse, or prescribe the use of Shi Gao or any other mineral product for the treatment of any medical condition. All decisions regarding medicinal use should be made in consultation with a qualified healthcare provider.