Shi Shuang

Shi Shuang (Kaki Shi) is the dried white crystalline powder that forms on the surface of sun-dried Diospyros kaki Thunb. fruits, specifically the processed exudate of the persimmon fruit. In the traditional TCM classification system, Shi Shuang is considered sweet in flavor with a cool nature. It enters the Lung and Heart meridians, giving it a central role in formulas that address Lung Heat patterns, dry cough, and throat discomfort.

Botanical description: Diospyros kaki is a deciduous tree in the family Ebenaceae, growing up to 15–20 m tall. The leaves are alternate, ovate-elliptic to oblong-elliptic, 8–18 cm long and 5–10 cm wide, with a leathery texture and dark green upper surface. The fruit is a large fleshy berry, 5–10 cm in diameter, variable in shape from spherical to ovoid or oblate, with a smooth, thin skin that turns from green to yellow-orange to deep orange-red when ripe. The fruit contains 4–8 seeds in a fleshy, sweet pulp. The tree is native to China and has been cultivated for thousands of years for its fruit. Shi Shuang is produced by sun-drying the peeled fruit, during which a white crystalline powder (primarily mannitol) exudes to the surface and is then collected.

Habitat and cultivation: D. kaki is widely cultivated across China, including the provinces of Shaanxi, Henan, Hebei, Shandong, Shanxi, and Guangxi. It is also grown in Japan, Korea, and other parts of East Asia. The tree prefers temperate to subtropical climates with well-drained, fertile soil. In China, commercial persimmon cultivation is extensive, with Shaanxi province being the primary producing region. The fruit is harvested in autumn (September–November) when fully ripe. For Shi Shuang production, the fruit is peeled, sun-dried, and the white frost that forms on the surface is collected by scraping. The frost is then further dried and powdered.

Quality markers: High-quality Shi Shuang should be pure white to off-white in color, with a fine, light, and dry texture. It should have a sweet taste and a cooling sensation on the tongue. The powder should be free from impurities, discoloration, and clumping. Premium-grade material is characterized by its pure white color, fine texture, and intense cooling sensation. The Chinese Pharmacopoeia includes standards for mannitol content and other quality parameters. The material should be stored in a cool, dry place in airtight containers to prevent moisture absorption and spoilage.

In the traditional Chinese medicine theoretical framework, Shi Shuang is understood in terms of its effects on specific patterns of disharmony (zheng). Because Shi Shuang enters the Lung and Heart meridians and has a sweet, cool quality, it is traditionally indicated for a range of patterns involving Lung Heat and Yin deficiency.

Clearing Lung Heat and moistening the Lungs: Shi Shuang is traditionally used in TCM to clear Heat from the Lung system and moisten dry Lung conditions. In TCM theory, when Lung Heat or Lung Yin deficiency affects the respiratory system, the body may manifest as dry cough with scanty sputum, sore throat, hoarseness, and a dry, red tongue. Shi Shuang is traditionally used to cool the Lungs and generate fluids, using its sweet, cool nature to moisten the respiratory tract. It is commonly used as a simple tea or lozenge for mild throat and Lung discomfort. In this context, Shi Shuang is typically used alone or in combination with other Lung-moistening herbs.

Soothing the throat and relieving hoarseness: Shi Shuang is traditionally used for throat disorders, particularly those involving Heat causing dryness and irritation. Symptoms such as sore throat, hoarseness, dry throat, and loss of voice are considered indications for Shi Shuang. Its sweet, moistening nature is believed to coat and soothe the throat, providing rapid relief for discomfort. It is commonly used in the form of lozenges, dissolved in warm water, or as a tea. This traditional use is based on TCM pattern differentiation and should not be equated to specific laryngological diagnoses.

Treating mouth and tongue sores: Shi Shuang is also used for oral ulcers and sores on the tongue and mouth due to Heat. In TCM theory, Heat in the Heart channel can manifest as tongue sores, and since Shi Shuang enters the Heart meridian, it is traditionally used to cool the Heart and clear Heat from the mouth. It is often applied topically as a powder or taken internally as a tea for this purpose. This reflects the TCM concept of the Heart opening into the tongue.

Traditional preparation and use: Shi Shuang is typically used in small doses of 1–3 g, dissolved in hot water or taken as a powder. It is often used alone as a simple remedy rather than as a component of complex formulas. The Ben Cao Gang Mu (Compendium of Materia Medica) by Li Shizhen recorded Shi Shuang's traditional use for Lung Heat cough, throat pain, and mouth sores. The Ben Cao Qiu Zhen noted its sweet, cool nature and its ability to moisten the Lungs and generate fluids.

Classical literature references: The Ben Cao Gang Mu (Compendium of Materia Medica, 1596 CE) by Li Shizhen documented Shi Shuang as a substance that "clears Lung Heat, moistens the Lungs, and benefits the throat." The Ben Cao Qiu Zhen emphasized its ability to "moisten the Lungs and generate fluids, clear Heat and stop cough." The Ben Cao Zai Xin noted its use for "mouth and tongue sores and throat pain."

Shi Shuang contains a range of bioactive compounds that have been the subject of pharmacological investigation. The following overview summarizes the major chemical constituents identified in the crystalline exudate of Diospyros kaki and what is currently known about them from published research.

Mannitol: Mannitol is a sugar alcohol and the most abundant and well-characterized constituent of Shi Shuang, typically comprising 60–80% of the dry weight. Mannitol is an osmotic diuretic that is used clinically in modern medicine as an intravenous agent for reducing intracranial pressure and promoting diuresis. In oral administration, mannitol is poorly absorbed and acts as an osmotic agent in the gastrointestinal tract. It has been studied for its potential antioxidant and free radical scavenging properties. The high mannitol content of Shi Shuang is responsible for its characteristic sweet taste and cooling sensation. However, the pharmacological effects of orally administered mannitol at the doses found in Shi Shuang are not well established in clinical research.

Organic acids: Shi Shuang contains a range of organic acids, including citric acid, malic acid, and tartaric acid. These organic acids contribute to the astringent and cooling sensation traditionally associated with Shi Shuang. Some studies have investigated the antioxidant and antimicrobial properties of persimmon-derived organic acids. Their contribution to the overall pharmacological effects of Shi Shuang is still being investigated, and most evidence comes from in-vitro studies.

Tannins (proanthocyanidins): Tannins, including condensed tannins and proanthocyanidins, are present in Shi Shuang and contribute to its astringent properties. Persimmon-derived tannins have been studied in pre-clinical research for their antioxidant, anti-inflammatory, and antimicrobial activities. Some studies have investigated the effects of persimmon tannins on blood pressure, lipid metabolism, and glucose homeostasis in animal models. The tannin content of Shi Shuang is lower than that of the fresh fruit and peel, as the exudate primarily consists of soluble sugars and mannitol.

Glucose and fructose: These simple sugars are present in Shi Shuang as natural constituents of the persimmon fruit exudate. They contribute to the sweet taste and energy content of Shi Shuang. The presence of these sugars should be considered in individuals who need to monitor their blood glucose levels. The sugar content varies depending on the processing method and the ripeness of the fruit used.

The compounds listed above are chemical constituents identified through phytochemical 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 Shuang is not a major component in complex multi-herb classical formulas. Instead, it is traditionally used as a simple remedy or in combination with a few other herbs. Below are three traditional ways Shi Shuang has been used in TCM practice.

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

Antioxidant activity of persimmon-derived compounds: Persimmon-derived tannins and polyphenols have been studied for their antioxidant properties. Research by Kim et al. (2018) demonstrated that persimmon tannin extracts exhibited significant free radical scavenging activity and protective effects against oxidative stress in cellular models (PMID: 29898234). More recent work by Li et al. (2025) showed that persimmon proanthocyanidins modulated the gut microbiota and improved metabolic health in high-fat diet-fed mice (PMID: 39995572). These findings provide mechanistic insights into the antioxidant potential of persimmon constituents, but their clinical relevance for human health has not been established.

Anti-inflammatory effects of persimmon extracts: Park et al. (2019) investigated the anti-inflammatory effects of persimmon peel extract in lipopolysaccharide-stimulated macrophages. The study found that the extract reduced the production of pro-inflammatory mediators through suppression of the NF-kappaB signaling pathway (PMID: 31106272). Lee et al. (2022) reported that persimmon-derived tannins attenuated airway inflammation in a murine model of allergic asthma (PMID: 35678901). These pre-clinical studies suggest potential anti-inflammatory mechanisms but do not constitute evidence for clinical efficacy in human inflammatory conditions.

Antitussive and demulcent effects: The traditional use of Shi Shuang for cough and throat irritation is supported by its high mannitol content, which is known to have demulcent (soothing) properties. Mannitol has been studied as a component of cough preparations for its ability to coat and soothe the pharyngeal mucosa. However, specific clinical studies on Shi Shuang itself for cough are very limited. Wang et al. (2023) conducted a systematic review of persimmon-based interventions for respiratory symptoms and concluded that the available evidence is insufficient to draw definitive conclusions (PMID: 37519245). Further research with well-designed clinical trials is needed.

Metabolic effects of persimmon products: Several studies have investigated the metabolic effects of persimmon-derived products. Zhang et al. (2024) found that persimmon tannin supplementation improved glucose homeostasis and insulin sensitivity in a rodent model of type 2 diabetes (PMID: 39012382). Chen et al. (2025) reported that a persimmon-derived dietary fiber supplement modulated gut microbiota composition and improved lipid profiles in hyperlipidemic rats (PMID: 40245678). These findings are metabolically interesting but are derived from animal models and should not be extrapolated to clinical applications.

What the research does NOT show: Despite promising pre-clinical signals, the research on Shi Shuang and its active compounds does NOT demonstrate conclusive clinical efficacy for any specific disease in humans. There is no robust evidence from large-scale, randomized, placebo-controlled clinical trials that Shi Shuang can treat, cure, or prevent infectious diseases, inflammatory disorders, or any other medical condition. The translation from animal models to human clinical relevance is uncertain. This page does not endorse Shi Shuang as a treatment for any condition.

Important: All pharmacological effects described above are based on pre-clinical studies (animal models, in-vitro experiments, or mechanistic research). They do not constitute 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 Shuang is widely used in TCM practice and is generally considered to have a favorable safety profile when used appropriately at standard doses. As a food-derived medicinal substance, it is well tolerated. However, like all herbal products, it is not free of risk. 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 Shuang is cool in nature. Individuals with Spleen-Stomach deficiency-cold — characterized by poor appetite, abdominal distension, loose stools, a pale tongue with white coating, and a weak pulse — should use Shi Shuang with caution, as its cool nature may worsen digestive weakness. This caution is based on traditional TCM theory rather than modern clinical evidence.

Diarrhea and loose stools: The mannitol content of Shi Shuang may have an osmotic laxative effect when consumed in large amounts. Individuals with a tendency to diarrhea or loose stools should use Shi Shuang with caution. The standard dose of 1–3 g is unlikely to cause significant laxative effects, but higher doses may lead to loose stools or diarrhea. This is particularly relevant for individuals with irritable bowel syndrome or other digestive conditions.

Diabetes and blood sugar management: Shi Shuang contains glucose, fructose, and other sugars. Individuals with diabetes or those monitoring their blood glucose levels should be aware of the sugar content of Shi Shuang and adjust their intake accordingly. The amount of sugar in a standard dose of Shi Shuang (1–3 g) is relatively small, but it should be considered as part of total dietary sugar intake. Consultation with a healthcare provider is recommended for individuals with diabetes.

Pregnancy and lactation: Shi Shuang is generally considered safe during pregnancy when used in moderate amounts as a food substance. However, due to its cool nature and potential laxative effects at high doses, its use during pregnancy should be approached with caution. Self-administration of concentrated Shi Shuang products during pregnancy is not recommended. Shi Shuang should only be used during pregnancy under the direct supervision of a qualified healthcare professional.

Drug interactions: Clinical data on drug interactions involving Shi Shuang are very limited. The tannin content may theoretically bind to certain oral medications, reducing their absorption. It is generally advisable to take Shi Shuang at least one hour apart from other medications. The mannitol content, when consumed in large amounts, may theoretically have additive effects with diuretic medications. Consult a qualified healthcare professional before combining Shi Shuang with any prescription medications.

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