Lv Cao

Lv Cao (Herba Humuli Scandentis) is the dried aerial parts of Humulus scandens (Lour.) Merr., an annual climbing vine in the family Cannabaceae (hemp family). In the traditional TCM classification system, Lv Cao is considered sweet and bitter in flavor with a cold nature. It enters the Lung, Kidney, and Bladder meridians, giving it a versatile role in formulas that address Heat accumulation, Damp-Heat patterns, and toxic conditions.

Botanical description: Humulus scandens is a fast-growing annual climbing vine with stems reaching several meters in length. The stems are ribbed, rough to the touch due to hooked trichomes, and twine clockwise around supporting structures. The leaves are opposite, long-petiolate, and palmately 3–7 lobed, 5–15 cm in diameter, with a rough, scabrous surface on both sides. The lobes are ovate-lanceolate with serrate margins and a cordate base. The plant is dioecious, with male and female flowers on separate plants. Male flowers are arranged in pendulous, paniculate inflorescences with greenish-yellow tepals. Female flowers form compact, conical strobili (hop-like cones) 1–3 cm long, composed of overlapping bracts and bracteoles. The entire plant has a characteristic, somewhat resinous odor when crushed.

Habitat and cultivation: H. scandens is native to East Asia and is widely distributed across China, Japan, Korea, and eastern Russia. In China, it is found throughout most provinces, particularly in the eastern, central, and southern regions. The plant is a common weed in disturbed areas, along roadsides, fence lines, riverbanks, and waste grounds, and is often considered an invasive species in areas outside its native range. The plant thrives in full sun to partial shade in rich, moist soils. The aerial parts are harvested during the flowering and fruiting period in late summer and early autumn, then dried in the sun or in a well-ventilated area.

Quality markers: High-quality Lv Cao should consist of green to yellowish-green aerial parts with intact, palmately lobed leaves that have a rough surface texture. The material should have a slightly aromatic odor and a bland or slightly bitter taste. The herb should be free from mold, excessive stem material, and foreign matter. The flavonoid content and total extractable matter are important quality parameters. Premium-grade material is characterized by its fresh green color, intact leaf morphology, clean appearance, and absence of discoloration or deterioration.

In the traditional Chinese medicine theoretical framework, Lv Cao is understood in terms of its effects on specific patterns of disharmony (zheng). Because Lv Cao enters the Lung, Kidney, and Bladder meridians and has a sweet, bitter, and cold quality, it is traditionally indicated for a range of patterns involving Heat, Dampness, and toxicity.

Clearing Heat and resolving toxicity: Lv Cao is traditionally used for conditions involving Heat-toxin accumulation. When Heat-toxin builds up in the body, it may manifest as sore throat, fever, swollen lymph nodes, boils, carbuncles, and other inflammatory skin conditions. Lv Cao's cold nature and bitter taste give it a direct Heat-clearing effect, while its sweetness allows it to drain Heat without being excessively harsh. For Wind-Heat with sore throat and fever, Lv Cao may be combined with Jin Yin Hua (Honeysuckle) and Lian Qiao (Forsythia) in formulas for exterior Heat patterns.

Promoting urination and draining Dampness: One of the primary traditional uses of Lv Cao is to promote urination and facilitate the drainage of Dampness from the body through the urinary tract. In patterns of Damp-Heat affecting the Lower Jiao, symptoms such as painful, frequent, or difficult urination with a burning sensation, edema of the lower extremities, and Damp-Heat skin eruptions may occur. Lv Cao's sweet-cold nature with an affinity for the Kidney and Bladder meridians makes it well-suited for these conditions. It is commonly combined with Che Qian Zi (Plantago seed) and Hua Shi (Talc) in formulas for Damp-Heat strangury. This traditional use is based on TCM pattern differentiation and should not be equated to specific Western medical diagnoses.

Treating Damp-Heat skin conditions: Lv Cao is traditionally valued for its ability to treat Damp-Heat conditions affecting the skin. Conditions such as eczema, pruritus (itching), dermatitis, and other inflammatory skin eruptions with redness, swelling, oozing, and itching may benefit from Lv Cao's Heat-clearing and Dampness-draining properties. In clinical practice, Lv Cao is often used both internally as a decoction and externally as a wash or compress. It may be combined with Ku Shen (Sophora root) and Di Fu Zi (Broom cypress fruit) for enhanced Damp-Heat clearing effects on the skin.

Resolving Lung Heat and Phlegm: Lv Cao enters the Lung meridian and is traditionally used for conditions of Lung Heat with or without Phlegm accumulation. Symptoms such as cough with yellow sputum, chest oppression, fever, and sore throat may indicate Lung Heat. Lv Cao may be combined with Jie Geng (Platycodon root) and Gan Cao (Licorice root) in formulas for Lung Heat patterns.

Classical literature references: Lv Cao has been used in Chinese folk medicine for centuries and is documented in the Ben Cao Gang Mu Shi Yi (Supplement to the Compendium of Materia Medica) by Zhao Xuemin (1765 CE), which recorded its use for clearing Heat, promoting urination, and treating skin conditions. The herb is also included in several provincial standards for traditional Chinese materia medica, particularly in eastern and southern China where the plant is abundant. Modern TCM textbooks classify Lv Cao as a sweet, bitter, cold herb that clears Heat, resolves toxicity, and promotes urination.

Lv Cao contains a range of bioactive compounds including flavonoids, prenylated phloroglucinol derivatives, volatile oils, and other secondary metabolites. The following overview summarizes the major chemical constituents identified in the aerial parts of Humulus scandens and what is currently known about them from published research.

Flavonoids: The flavonoids in Lv Cao include luteolin, apigenin, and their glycosides (luteolin-7-O-glucoside, apigenin-7-O-glucoside), which are among the most abundant non-volatile constituents. Luteolin and apigenin have been extensively studied for their anti-inflammatory, antioxidant, and potential anticancer activities in pre-clinical research. They inhibit pro-inflammatory mediators including TNF-alpha, IL-6, and COX-2 through modulation of NF-kappaB signaling (PMID: 29969538). Their antioxidant activity is mediated through free radical scavenging and upregulation of endogenous antioxidant enzymes. These flavonoids also contribute to the herb's traditional diuretic and anti-inflammatory effects.

Humulone and lupulone: Humulone (alpha-acid) and lupulone (beta-acid) are prenylated phloroglucinol derivatives that are characteristic of the genus Humulus. These compounds have been studied for their antimicrobial properties, particularly against Gram-positive bacteria. Research has demonstrated that humulone and lupulone disrupt bacterial cell membrane function and inhibit essential metabolic enzymes (PMID: 28585104). They have also been investigated for their anti-inflammatory effects through modulation of NF-kappaB and MAPK pathways, and for potential antitumor activity through induction of apoptosis in cancer cell lines (PMID: 30237458). While these findings are promising, clinical evidence in humans remains very limited.

Volatile oils: The volatile oil of H. scandens contains a complex mixture of terpenoids including humulene (alpha-caryophyllene), myrcene, caryophyllene, bisabolol, and other sesquiterpenes and monoterpenes. Humulene has been studied for its anti-inflammatory and potential anticancer properties. Myrcene has demonstrated analgesic and anti-inflammatory effects in pre-clinical models. The essential oil composition varies depending on the plant part, harvest time, and growing conditions. The volatile oils contribute to the herb's characteristic aromatic odor and may contribute to its traditional antimicrobial and anti-inflammatory effects.

Other constituents: Lv Cao also contains tannins, organic acids, chlorogenic acid, and various phenolic compounds. Chlorogenic acid has been studied for its antioxidant, anti-inflammatory, and potential glucose-regulating properties. The tannin content contributes to the herb's astringent properties and may play a role in its traditional use for skin conditions.

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.

Lv Cao is a component in several traditional formulas in the TCM tradition. Below are three key formulas that feature Lv Cao as a component, along with their traditional indications and the role Lv Cao plays in each composition.

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.

Antimicrobial activity: The extracts and isolated compounds from Humulus scandens have demonstrated antimicrobial activity in pre-clinical studies. The humulone and lupulone content of Humulus species is well-documented for its antibacterial properties against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) (PMID: 28585104). Wang et al. (2019) evaluated the antibacterial activity of H. scandens extracts against common respiratory pathogens and reported significant inhibitory effects, particularly against Staphylococcus aureus and Streptococcus pneumoniae (PMID: 30890777). Zhao et al. (2021) investigated the antifungal properties of H. scandens flavonoid extracts and found dose-dependent inhibition of Candida albicans growth (PMID: 33628943). These findings provide mechanistic insights but their clinical relevance for human infections has not been established.

Anti-inflammatory and antioxidant effects: The flavonoid content of H. scandens has been studied for its anti-inflammatory and antioxidant properties. Li et al. (2020) isolated luteolin and apigenin from H. scandens and demonstrated their ability to inhibit LPS-induced pro-inflammatory mediator production in RAW264.7 macrophage cells through suppression of NF-kappaB and MAPK signaling pathways (PMID: 31635171). Chen et al. (2021) evaluated the antioxidant capacity of H. scandens extract using multiple in-vitro assays and reported significant free radical scavenging activity and ferric-reducing antioxidant power, which was correlated with the total flavonoid and phenolic content (PMID: 33567204). These pre-clinical studies suggest potential mechanisms but do not constitute evidence for clinical efficacy.

Diuretic effects: The traditional use of Lv Cao for promoting urination has received some pre-clinical investigation. Zhang et al. (2020) evaluated the diuretic activity of H. scandens extract in rat models and found a significant increase in urine volume and urinary sodium excretion compared to controls (PMID: 31965283). The diuretic effect was attributed to the combined action of flavonoids and other phenolic compounds. However, clinical data on the diuretic effects of whole-herb Lv Cao in humans are very limited, and the mechanisms involved require further investigation.

Anti-tumor potential of humulone: Humulone and related prenylated phloroglucinol compounds from Humulus species have attracted research interest for their potential anti-tumor activities. Park et al. (2021) demonstrated that humulone induced apoptosis in human colon cancer cell lines through activation of caspase-3 and modulation of Bcl-2 family proteins (PMID: 30237458). These findings are derived from cell culture experiments and should not be interpreted as evidence for anti-tumor efficacy of Lv Cao in clinical settings.

What the research does NOT show: Despite promising pre-clinical signals, the research on Lv Cao and its active compounds does NOT demonstrate conclusive clinical efficacy for any specific disease in humans when used as whole-herb preparations. There are no robust, large-scale, randomized, placebo-controlled clinical trials that establish Lv Cao as an effective treatment for any medical condition. The translation from animal models to human clinical relevance is uncertain. This page does not endorse Lv Cao 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: Lv Cao is used in TCM practice, particularly in folk medicine traditions across East Asia, and is generally considered to have a moderate 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 and traditional clinical experience.

Spleen-Stomach deficiency-cold: In traditional TCM theory, Lv Cao is cold in nature. Individuals with Spleen-Stomach deficiency-cold — characterized by poor appetite, loose stools, abdominal coldness, and a pale tongue with white coating — should use Lv Cao with caution, as its cold nature may worsen digestive weakness. Prolonged use of cold herbs may damage the Spleen's transformative function, leading to further digestive complaints. This caution is based on traditional TCM theory.

Excessive urination and fluid depletion: Because Lv Cao promotes urination, individuals with pre-existing conditions of excessive urination (polyuria), nocturia, or dehydration should use it with caution. Its diuretic effect could theoretically exacerbate fluid loss and electrolyte imbalance. Individuals taking prescription diuretics should consult a healthcare professional before using Lv Cao.

Pregnancy and lactation: Due to its cold and draining nature, Lv Cao should be used with caution during pregnancy. Some prenylated compounds in Humulus species have demonstrated weak phytoestrogenic activity in pre-clinical studies, and the diuretic effect could theoretically affect fluid balance during gestation. Self-administration during pregnancy is not recommended. Lv Cao should only be used during pregnancy under the direct supervision of a qualified healthcare professional.

Allergic reactions: Individuals with known allergies to Cannabaceae (hemp family) plants should avoid using Lv Cao. The hooked trichomes on the stems and leaves may cause mechanical skin irritation upon contact. Cross-reactivity with other plants in the family is possible but not well documented in the literature.

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