Chan Tui

Chan Tui (Periostracum Cicadae) is the shed exoskeleton (exuviae) of the cicada nymph, primarily obtained from Cryptotympana pustulata Fabricius, an insect species in the family Cicadidae. In the traditional TCM classification system, Chan Tui is considered sweet and salty in flavor with a cool nature. It enters the Lung and Liver meridians, giving it a central role in formulas that address Wind-Heat exterior patterns, Liver Wind convulsions, swelling, and ocular nebula.

Zoological description: Cryptotympana pustulata is a large cicada species native to East Asia, including China, Japan, Korea, and parts of Southeast Asia. The adult cicada has a black body with golden-brown markings and transparent wings with prominent venation. The nymphal stage lasts several years underground, during which the nymph feeds on root sap from deciduous trees. When the nymph is ready to undergo its final molt, it emerges from the ground, climbs onto a tree trunk or vertical surface, and splits its exoskeleton along the dorsal midline. The adult cicada emerges from this shell, leaving behind a complete, hollow exuviae that retains the morphological features of the nymph — including the head, compound eye sockets, antennae, thorax, wing pads, and leg segments. This abandoned exoskeleton constitutes the medicinal material Chan Tui.

Collection and processing: Chan Tui is collected during the summer months (June to September), when cicada nymphs emerge from the ground in large numbers to molt. The exuviae are gathered by hand from tree trunks, branches, and low vegetation. After collection, the exoskeletons are carefully cleaned of soil, plant debris, and any residual insect tissue, then dried in the sun or under controlled conditions. The dried material is light brown to yellowish-brown, translucent in thin sections, and extremely light and brittle. The Chinese Pharmacopoeia specifies that Chan Tui should be complete in structure, free from significant breakage, and free from mold, insect damage, and foreign matter. The material is typically stored in dry, sealed containers away from direct sunlight.

Quality markers: The Chinese Pharmacopoeia (2020 edition) includes a monograph for Periostracum Cicadae specifying quality standards including morphology, color, odor, and taste. High-quality Chan Tui is characterized by a complete, intact exuviae with a light brownish-yellow color, translucent texture, and a faint, characteristic odor. The material should be free from adhering soil, mold, and insect damage. Chemical identification methods including thin-layer chromatography (TLC) are specified for authentication purposes. The N-acetyldopamine content and chitin composition are increasingly used as chemical markers for quality assessment in modern research.

In the traditional Chinese medicine theoretical framework, Chan Tui is understood in terms of its effects on specific patterns of disharmony (zheng). Because Chan Tui enters the Lung and Liver meridians and has a sweet, salty, and cool quality, it is traditionally indicated for a range of patterns involving Wind-Heat, Liver Wind, and accumulations of toxic Heat.

Releasing exterior Wind-Heat: Chan Tui is considered a key herb in TCM for dispersing Wind-Heat from the exterior of the body. In TCM theory, when Wind-Heat invades the exterior, it may manifest as fever, headache, sore throat, redness of the eyes, and a floating rapid pulse. Chan Tui is traditionally used to release this exterior pathogen and is particularly valued for its ability to address symptoms affecting the upper body, including the head, eyes, and throat. It is commonly combined with Bo He (Mentha haplocalyx), Jing Jie (Schizonepeta tenuifolia), and Ju Hua (Chrysanthemum morifolium) to enhance the Wind-Heat dispersing effect. Chan Tui is considered especially useful for Wind-Heat patterns accompanied by hoarseness, loss of voice, or skin rashes such as urticaria.

Extinguishing Liver Wind and stopping convulsions: Chan Tui enters the Liver meridian and is traditionally used to extinguish Liver Wind and arrest convulsions. In TCM theory, when Liver Wind stirs internally, it may manifest as muscle spasms, tremors, convulsions, tetanus-like symptoms, and infantile febrile seizures. Chan Tui is believed to calm the Liver and settle Wind, making it a traditional choice for pediatric convulsions and febrile seizure patterns. It is historically recorded in the Ben Cao Gang Mu as a treatment for infantile convulsions and tetanus. In modern clinical practice, Chan Tui may be combined with other Liver-calming agents such as Tian Ma (Gastrodia) and Quan Xie (Scorpion) for more severe presentations.

Reducing swelling and promoting eruption of rashes: Chan Tui is traditionally used to reduce swelling and promote the eruption of skin rashes in conditions such as measles, urticaria, and other exanthematous diseases. In TCM theory, when exterior Wind-Heat is not fully released, it may manifest as skin rashes that are slow to erupt or are accompanied by intense itching and swelling. Chan Tui is believed to help the rash surface properly, thereby resolving the external pathogen and alleviating discomfort. It is often combined with Jin Yin Hua (Lonicera japonica) and Bo He for Wind-Heat skin conditions.

Eliminating nebula and improving vision: Chan Tui has a traditional reputation for treating ocular disorders, particularly corneal opacity (nebula) and visual obstruction. In TCM theory, when Wind-Heat or Liver Fire ascends to the eyes, it may cause redness, pain, photophobia, and the formation of nebula that impairs vision. Chan Tui is believed to dispel Wind-Heat from the Liver channel and eliminate nebula, thereby improving vision. It is commonly combined with Ju Hua, Jing Jie, and other Liver-clearing herbs in formulas for ocular conditions. The classical text Shen Nong Ben Cao Jing records Chan Tui's traditional use for "eliminating nebula and reversing opacity."

Classical literature references: The Shen Nong Ben Cao Jing (Divine Farmer's Materia Medica Classic, circa 200 CE) records Chan Tui's traditional use for "eliminating nebula, reversing opacity, and treating infantile convulsions." The Ben Cao Gang Mu (Compendium of Materia Medica, 1596 CE) by Li Shizhen expanded on these traditional applications, noting Chan Tui's ability to "dispel Wind-Heat, calm the Liver, stop convulsions, reduce swelling, and eliminate nebula." The Ben Cao Bei Yao further describes Chan Tui's traditional use for hoarseness, loss of voice, and skin rashes.

Chan Tui contains a range of distinctive chemical constituents that reflect its origin as an insect exoskeleton. The following overview summarizes the major classes of compounds identified in Periostracum Cicadae and what is currently known about them from published research.

N-acetyldopamine (NADA) polymers: The most characteristic and pharmacologically distinctive compounds in Chan Tui are N-acetyldopamine (NADA) polymers and their oligomeric derivatives. These compounds are produced during the sclerotization (hardening) process of the insect cuticle and are unique markers of insect-derived medicinal materials. Recent phytochemical studies have isolated and structurally characterized a range of NADA dimers, trimers, and higher-order oligomers from Chan Tui, including cicadamides and percicamides. These compounds have been investigated in pre-clinical studies for potential anti-inflammatory, antioxidant, and neuroprotective activities. The NADA content is increasingly used as a chemical marker for quality assessment of Periostracum Cicadae.

Chitin: Chitin is a linear polysaccharide composed of N-acetylglucosamine units that forms the primary structural component of the arthropod exoskeleton, including the cicada exuviae. Chan Tui contains a significant proportion of chitin, which contributes to its structural integrity and physical properties. Chitin and its deacetylated derivative chitosan have been studied for a range of biomedical applications, including wound healing, antimicrobial activity, and drug delivery. A recent study (2025) successfully developed a Periostracum Cicadae chitosan-based oriented hydrogel for rapid hemostasis and wound healing, demonstrating the potential biomedical utility of this natural polymer.

Amino acids and trace elements: Chan Tui contains a range of amino acids, including alanine, glycine, glutamic acid, aspartic acid, and others, which are derived from the protein components of the insect cuticle. The material also contains trace elements such as calcium, magnesium, zinc, and iron. These nutritional components are present in relatively small quantities and are not considered primary pharmacologically active constituents, but they may contribute to the overall nutritional and mineral profile of the material.

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.

Chan Tui is a component of several classical and modern TCM formulas, though it is more commonly used as part of combination therapies rather than as a standalone herb. Below are key formulas and preparation methods that feature Chan Tui as a significant component, along with their traditional indications.

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.

Immunosuppressive and anti-inflammatory effects: A study by Lin et al. (2024) published in the Journal of Ethnopharmacologyinvestigated the immunosuppressive effects of Periostracum Cicadae on dendritic cells and contact hypersensitivity responses. The study found that Chan Tui extract inhibited dendritic cell activation and maturation, and suppressed contact hypersensitivity responses in a mouse model (PMID: 39270880). These findings provide mechanistic insights into the traditional use of Chan Tui for allergic and inflammatory skin conditions. However, these results are from pre-clinical models and their clinical relevance in humans has not been established.

Sleep regulation and insomnia: A study by Wang et al. (2024) published in Molecules investigated the effects of Periostracum Cicadae extract and N-acetyldopamine on sleep-related neurotransmitters in PCPA-induced insomnia rats (PMID: 39125043). The study reported that Chan Tui extract regulated levels of serotonin, dopamine, and other neurotransmitters in the rat brain, suggesting a potential mechanism for its traditional use in calming the spirit and treating insomnia and night crying in children. These findings are from animal models and require further validation in human studies.

Anti-tumor and gastric protection: Liang et al. (2025) published a study in Pharmaceuticals investigating the effects of Periostracum Cicadae on c-Fos/c-Jun signaling pathways and the inhibition of epithelial-mesenchymal transition (EMT) in gastric tissue (PMID: 40283972). The study explored the potential mechanisms underlying the traditional use of Chan Tui for chronic atrophic gastritis (CAG). The findings suggest that Chan Tui may inhibit EMT through modulation of AP-1 signaling pathways, though these results are from pre-clinical experiments and do not constitute clinical evidence for efficacy in treating gastric conditions in humans.

Parkinson's disease research: Li et al. (2025) published a metabolomics-based study in the International Journal of Molecular Sciences investigating the pharmacodynamic mechanisms of Cicadae Periostracum in Parkinson's disease (PD) models (PMID: 39859260). The study identified metabolic pathways modulated by Chan Tui treatment in PD animal models, including neurotransmitter and energy metabolism pathways. While these findings are scientifically interesting, they represent early-stage pre-clinical research and do not support the use of Chan Tui for treating Parkinson's disease in humans.

Wound healing and biomedical applications: Lei et al. (2025) published a study in Carbohydrate Polymers describing the development of a silver nanoparticle-loaded oriented hydrogel based on Periostracum Cicadae chitosan for rapid hemostasis and wound healing (PMID: 40383563). This innovative biomedical application demonstrates the potential of chitin-derived materials from Chan Tui in tissue engineering and wound management. However, this is a materials science study and does not evaluate the traditional oral use of Chan Tui.

What the research does NOT show: Despite these pre-clinical studies, the research on Chan Tui 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 Chan Tui can treat, cure, or prevent any medical condition. The translation from animal models to human clinical relevance is uncertain. This page does not endorse Chan Tui 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: Chan Tui is widely used in TCM practice and is generally considered to have a favorable safety profile when used appropriately under professional guidance. However, as an insect-derived material, it presents specific considerations that differ from plant-based herbs. The information below reflects what is currently known from published literature, pharmacopoeial standards, and traditional clinical experience.

Qi deficiency patterns: In traditional TCM theory, Chan Tui has a dispersing nature that may further deplete Qi in individuals with significant Qi deficiency. Individuals with chronic fatigue, weak pulse, low energy, and a tendency to catch colds easily should use Chan Tui with caution. The dispersing (wind-releasing) action of Chan Tui is considered potentially inappropriate in cases where the body's Qi is already deficient, as it may further scatter the defensive Qi. Chan Tui should only be used under professional guidance with appropriate Qi-tonifying herbs when Qi deficiency coexists with Wind-Heat patterns.

Spleen deficiency and digestive weakness: Individuals with Spleen deficiency patterns — characterized by poor appetite, loose stools, abdominal distension, and fatigue — should use Chan Tui with caution. Its cool nature may theoretically aggravate digestive weakness in susceptible individuals. In TCM practice, Chan Tui is typically combined with Spleen-tonifying or Qi-regulating herbs when used in patients with underlying digestive weakness.

Pregnancy and lactation: Chan Tui does not have a specific traditional contraindication during pregnancy, but its use in pregnant women should be approached with caution. In TCM theory, strong exterior-releasing and Liver-calming herbs are generally used conservatively during pregnancy. Modern pharmacological data on Periostracum Cicadae constituents in pregnancy are insufficient to establish safety. Do not use Chan Tui during pregnancy or lactation without direct supervision from a qualified healthcare professional.

Drug interactions: Data on drug interactions involving Chan Tui are very limited. Pre-clinical studies suggest that certain N-acetyldopamine derivatives in Chan Tui may theoretically affect cytochrome P450 enzyme activity, which could alter the metabolism of drugs processed through these pathways. There is also theoretical potential for additive effects when combined with sedatives, anticonvulsants, or anticoagulant medications, given Chan Tui's traditional effects on the Liver and nervous system. Additionally, because Chan Tui has been studied for potential immunosuppressive effects, there is theoretical potential for interactions with immunosuppressive or immunomodulatory medications. Well-documented clinical interaction data for Chan Tui in humans are lacking. Consult a qualified healthcare professional before combining Chan Tui with any prescription medications.

Allergic reactions: As an insect-derived material, Chan Tui carries a theoretical risk of allergic reactions in sensitive individuals, particularly those with known allergies to insect products, shellfish, or chitin-containing materials. Symptoms of allergic reactions may include skin rash, itching, urticaria, or, in rare cases, more severe hypersensitivity reactions. Individuals with a history of allergic reactions to insect stings, dust mites, or shellfish should exercise caution. Any suspected adverse effects should be reported to a healthcare professional.

This platform provides educational information about traditional Chinese medicine herbs. It does not recommend, endorse, or prescribe the use of Chan Tui 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.