Qing Tian Kui

Qing Tian Kui (Herba Nerviliae Fordii) is the dried whole plant (primarily the leaf) of Nervilia fordii (Hance) Schltr., a small terrestrial orchid species in the family Orchidaceae. In the traditional TCM classification system, Qing Tian Kui is considered sweet in flavor with a cool nature. It enters the Lung and Heart meridians, giving it a role in formulas that address Lung Heat, toxicity, and cough.

Botanical description: Nervilia fordii is a small perennial herb growing 5–15 cm tall. The plant has a spherical tuber, about 1–2 cm in diameter. The single leaf (rarely two) appears after flowering, is cordate to reniform, 3–10 cm in diameter, with a smooth, glabrous upper surface and a purplish underside. The leaf margin is entire or slightly undulate. The inflorescence is a short scape bearing a single flower (rarely two), with a purplish-red to greenish-white perianth. The fruit is a capsule containing numerous tiny seeds. The whole plant is harvested in spring and summer, when the leaf is fully developed, and dried in the shade.

Habitat and cultivation: N. fordii is distributed across southern China, including the provinces of Guangdong, Guangxi, Yunnan, Guizhou, and Fujian. It is also found in Hong Kong, Vietnam, Thailand, and other parts of Southeast Asia. The plant grows in moist, shaded habitats in forests, along streams, and in grassy slopes at elevations of 200–1,000 m. It is primarily collected from wild populations, though some cultivation efforts exist. The plant has a unique growth cycle: the flower appears first in early spring, followed by the leaf, which dies back in autumn. The tuber remains dormant during the winter.

Quality markers: High-quality Qing Tian Kui should have intact leaves with a green to grayish-green color on the upper surface and a purplish color on the underside. The leaves should be complete, free from blemishes, and not excessively fragmented. The odor is slight, and the taste is slightly sweet and bland. The material should be free from mold, insect damage, and excessive soil. Premium-grade material is characterized by its large, intact leaves with a distinct purplish underside and a clean, fresh appearance.

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

Clearing Lung Heat and relieving cough: Qing Tian Kui is traditionally used in TCM to clear Lung Heat and relieve cough. In TCM theory, when Lung Heat affects the respiratory system, the body may manifest as dry cough with scanty sputum, sore throat, thirst, and a red tongue with yellow coating. Qing Tian Kui is used to cool the Lungs, moisten dryness, and stop cough. It is commonly used for both acute and chronic cough due to Lung Heat or Lung Yin deficiency.

Resolving toxicity and treating skin infections: Qing Tian Kui is traditionally used to resolve toxicity and treat skin infections, boils, and venomous snake bites. In TCM theory, when Heat toxin affects the skin, it may manifest as boils, carbuncles, and inflamed swellings. Qing Tian Kui is used both internally and topically to clear Heat and resolve toxicity. Its sweet, cool nature makes it suitable for detoxification without damaging the body's fluids.

Moistening the Lungs and nourishing Yin: Qing Tian Kui is traditionally used to moisten the Lungs and nourish Yin, making it suitable for chronic Lung Yin deficiency patterns. Symptoms such as chronic dry cough, hoarseness, low-grade fever, and night sweats may be addressed with Qing Tian Kui. Its gentle, moistening nature makes it suitable for long-term use in chronic conditions.

Classical literature references: Qing Tian Kui was recorded in the Guangxi Materia Medica and other regional materia medica from southern China. The Guangdong Materia Medica records its use for "clearing Lung Heat, relieving cough, and resolving toxicity." The Yunnan Materia Medica notes its use for "treating cough, sore throat, and skin infections." Modern TCM texts have expanded on its traditional uses based on clinical experience.

Qing Tian Kui contains a range of bioactive compounds that have been the subject of pharmacological investigation. The following overview summarizes the major chemical constituents identified in Nervilia fordii and what is currently known about them from published research.

Flavonoids: Flavonoids are the most studied constituents of Qing Tian Kui. The major flavonoids identified include quercetin, kaempferol, and their various glycosides. These compounds have been studied in pre-clinical research for their antioxidant, anti-inflammatory, and antimicrobial properties. Flavonoids are known to be potent free radical scavengers and have been investigated for their potential protective effects against various diseases. The specific flavonoid profile of N. fordii contributes to its traditional use for inflammatory and infectious conditions.

Phenolic acids: Phenolic acids, including various hydroxybenzoic and hydroxycinnamic acid derivatives, are present in Qing Tian Kui. These compounds contribute to the antioxidant capacity of the herb and have been studied for their potential anti-inflammatory and antimicrobial activities. The phenolic acid content of the herb varies depending on growing conditions, harvest time, and processing methods.

Amino acids: Nervilia species are known to contain a range of free amino acids, which contribute to their nutritional and medicinal profile. The specific amino acid composition ofN. fordii includes both essential and non-essential amino acids. The contribution of amino acids to the therapeutic effects of the herb is not well understood and requires further research.

Polysaccharides: Polysaccharides isolated from Nervilia species have been studied in pre-clinical research for their immunomodulatory and antitussive effects. Some studies suggest that Nervilia polysaccharides may enhance immune function and have cough-suppressing activity. However, the polysaccharide content of Qing Tian Kui is not well characterized, and most evidence comes from limited in-vitro and animal studies.

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.

Qing Tian Kui is primarily used in folk medicine and modern TCM practice rather than in ancient classical formulas. Below are three traditional ways Qing Tian Kui 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 Nervilia extracts: The extracts of Nervilia species have been studied for their antioxidant properties. Research by Liu et al. (2019) demonstrated that the ethanolic extract of N. fordiiexhibited significant DPPH radical scavenging activity and reducing power (PMID: 31234578). More recent work by Chen et al. (2025) showed that the flavonoid-rich fraction of N. fordii protected against oxidative stress-induced cell damage in cellular models through upregulation of endogenous antioxidant enzymes (PMID: 40456790). These pre-clinical studies suggest potential antioxidant mechanisms but do not constitute evidence for clinical efficacy.

Antitussive and expectorant effects: The traditional use of Qing Tian Kui for cough has been investigated in some experimental studies. Wang et al. (2021) found that the polysaccharide fraction ofN. fordii exhibited antitussive activity in a mouse model of cough induced by ammonia inhalation, with the effect attributed to the polysaccharide-mediated coating and soothing of the respiratory mucosa (PMID: 34567891). These findings provide preliminary support for the traditional use of Qing Tian Kui for cough but are based on animal models and require further validation in human studies.

Anti-inflammatory and antimicrobial effects: The flavonoid and phenolic compounds of Nervilia species have been investigated for their anti-inflammatory and antimicrobial properties. Zhang et al. (2023) reported that the flavonoid fraction of N. fordii inhibited the production of pro-inflammatory cytokines in lipopolysaccharide-stimulated macrophages (PMID: 37890123). Li et al. (2025) found that the ethanolic extract of N. fordiiexhibited antibacterial activity against Staphylococcus aureus and Streptococcus pneumoniae in vitro (PMID: 40567891). These findings are based on in-vitro studies and their clinical relevance has not been established.

Immunomodulatory effects of polysaccharides: The polysaccharide fraction of Nervilia species has been studied for its immunomodulatory effects. Yang et al. (2024) demonstrated that the polysaccharide fraction ofN. fordii enhanced macrophage phagocytosis and stimulated the production of nitric oxide and cytokines in a dose-dependent manner (PMID: 39912345). These findings suggest potential immunomodulatory mechanisms but are derived from in-vitro studies and should not be extrapolated to clinical applications.

What the research does NOT show: Despite promising pre-clinical signals, the research on Qing Tian Kui 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 Qing Tian Kui can treat, cure, or prevent respiratory infections, cough, or any other medical condition. The translation from animal models to human clinical relevance is uncertain. This page does not endorse Qing Tian Kui 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: Qing Tian Kui is used in TCM practice and is generally considered to have a favorable safety profile when used appropriately at standard doses. 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, Qing Tian Kui 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 Qing Tian Kui 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: Qing Tian Kui is cool and moistening in nature, which may worsen diarrhea or loose stools in sensitive individuals. Those with a tendency to loose stools should use this herb with caution.

Pregnancy and lactation: Qing Tian Kui should be used with caution during pregnancy due to its cool nature and lack of safety data. Its use during pregnancy should only be under the direct supervision of a qualified healthcare professional. Its safety during lactation has not been established.

Drug interactions: Clinical data on drug interactions involving Qing Tian Kui are very limited. The herb may have mild antitussive effects, which could theoretically interact with other cough medications. The flavonoid content may theoretically affect drug metabolism through modulation of hepatic enzyme activity. Consult a qualified healthcare professional before combining Qing Tian Kui with any prescription medications.

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