Traditionally used for
- Cough & breathing
- Digestion
- Urinary & fluids
- Menstrual & women's health
☯ TCM Properties
Promotes urination, resolves Dampness and c lears Heat; Promotes lactation
Traditional Chinese Uses
This entry corresponds to Tong Cao, the dried stem pith of Tetrapanax papyrifer (Araliaceae), the rice-paper plant. Sweet and bland with a cold nature, it enters the Lung and Stomach channels to promote urination and drain Dampness, clear Heat, and promote lactation. It is a gentle herb for damp-heat and heat patterns of painful, difficult or dribbling urination (lin syndrome) and for edema, and it is especially valued to promote breast-milk flow in postpartum women with scanty milk, where it is combined with tonics such as Wang Bu Liu Xing and pig-trotter soups.
Being mild, it is usually decocted in modest doses and paired with stronger diuretic or nourishing herbs.
Relationships
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Botanical Description
This entry's botanical identity is not established in the major TCM materia medica references available to the editor. The pinyin name "Geng Tong Cao" is not a standard heading in the principal contemporary materia medica (Bensky, Chen, Chinese Pharmacopoeia) and does not correspond unambiguously to a single recognised herb; the literal sense of the characters suggests a folk medicinal plant associated with relief of pain and stagnation, but no definitive species attribution can be recorded here. The dataset field for scientific name is "Unknown," and no reliable cross-reference to a Latin binomial, plant family, habit, morphology, or geographic distribution can be supplied without further source confirmation. Editorial fields are therefore left empty pending verification.
Active Constituents
Lignocellulosic parenchyma (cellulose and lignin)
Structural plant polysaccharide and polyphenolic polymerConcentration: The bulk of the dried pith by weight
The pith is essentially a honeycomb of thin-walled parenchyma, and its cellulose is in the native cellulose I crystalline form. This is why the drug is almost weightless, why it absorbs many times its weight of water, and why it is used industrially as a lignocellulose skeleton for aerogels and dye biosorbents. Pharmacologically it behaves as bulk insoluble fibre in decoction rather than as an active principle, which is a large part of why the drug is regarded as bland and mild.
Hederagenin
Oleanane pentacyclic triterpene sapogeninConcentration: Described as one of the main components of the crude drug; no pharmacopoeial content limit is set
Given orally to rats with chronic constriction injury of the sciatic nerve, hederagenin reduced mechanical, thermal and cold hyperalgesia and lowered dorsal root ganglion expression of TRPM8, TRPA1, TRPV1, TRPV4 and phosphorylated p38 MAPK, mirroring the effect of the whole crude drug. Animal data only.
Sesquiterpene essential oil
Sesquiterpene hydrocarbonsConcentration: Sesquiterpenoids about 96 percent of the oil, with beta-cubebene about 14 percent, caryophyllene about 13 percent, alpha-cubebene about 12 percent, copaene about 8 percent and delta-cadinene about 7 percent
Sixty-one compounds were identified by gas chromatography-mass spectrometry in an essential oil of this species, with modest antioxidant activity and weak alpha-glucosidase inhibition (about 18 percent at 500 micrograms per millilitre). The source publication does not state which plant part the oil was distilled from, so this profile should not be assumed to describe the pith, which is not an aromatic drug and is not used as an oil source.
⚠ Drug Interactions
Tong Cao (Medulla Tetrapanacis)
This record's binomial and Latin name, Tetrapanax papyrifer and Medulla Tetrapanacis, are exactly those of Tong Cao: the dried stem pith of the rice-paper plant. Any record carrying both of those identifiers describes the same drug from the same plant part, whatever pinyin heading it sits under. If both appear in one formula or one database, the same material is being counted twice.
Clinical note: Treat this and Tong Cao as one drug unless a supplier can demonstrate a different plant part. Do not add the two doses together.
Geng Tong Cao as defined in Chinese materia medica (Aeschynomene indica stem xylem)
In standard Chinese materia medica the name geng tong cao does not refer to Tetrapanax at all. It is first recorded in Yin Pian Xin Can of 1935 as the pith-like woody core of the stem of Aeschynomene indica L., a legume, harvested in September and October by pulling the plant up, stripping the bark and drying the wood; its listed synonyms are bai geng tong, ye tong cao, qi tong cao and shui tong cao. That is a different family, a different plant and a different tissue from the Araliaceae stem pith named by the binomial and Latin name on this record. The two drugs share only the word tong cao, meaning a light pith that unblocks; the same word also attaches to Xiao Tong Cao from Stachyurus and Helwingia, so the syllable carries no botanical information at all.
Clinical note: Do not accept geng tong cao as a botanical identification. Ask the supplier for the binomial and the plant part, and if the answer is Aeschynomene indica the material is not what this record describes and its evidence base does not apply to it.
Xiao Tong Cao (Stachyurus chinensis and Helwingia japonica pith)
Xiao Tong Cao is a separate pharmacopoeial drug taken from the stem pith of Stachyurus chinensis, Stachyurus himalaicus or Helwingia japonica. It looks like a thinner version of Tong Cao, is cheaper, and is a routine commercial stand-in. Because both are white, near-weightless piths with no taste and no aroma, they cannot be told apart by the ordinary sensory checks used at dispensing.
Clinical note: Buy against a botanical certificate rather than appearance. If a consignment of tong cao arrives in unusually thin sticks, treat it as unidentified until confirmed.
Mu Tong and Guan Mu Tong (Aristolochia manshuriensis)
The names moved historically. As Li Shizhen states in the Ben Cao Gang Mu, what is now called tong cao is the classical tong tuo mu, while what the old books called tong cao is what is now called mu tong. A pre-Song prescription reading tong cao therefore specifies Akebia stem, not Tetrapanax pith. That matters because mu tong itself was widely adulterated with Guan Mu Tong from Aristolochia manshuriensis, which caused a large series of end-stage renal failure in China and whose drug standard was cancelled by the Chinese regulator in 2003. A reader who resolves a classical tong cao to mu tong and then buys mu tong from an unverified source can end up dispensing an aristolochic acid drug.
Clinical note: When working from a classical text, resolve the name to a binomial before ordering. Never substitute mu tong for tong cao or the reverse, and if mu tong is genuinely required, insist on Akebia or Clematis material with aristolochic acid testing.
Diuretics
The pith is prescribed traditionally to promote urination, but there is no controlled human or animal study measuring urine output, sodium excretion or renal clearance for this drug. The interaction is listed as theoretical on the strength of the traditional indication alone; absence of a study is not evidence that the herb is inert.
Clinical note: No specific action is needed, but do not assume a measurable diuretic effect either. If a patient is on a diuretic and volume status matters, monitor rather than reason from the traditional category.
Evidence Tier
Moderate evidence · 3 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
0 verified · 3 unverified
Show 3 studies
- Medulla Tetrapanacis water extract alleviates inflammation and infection by regulating macrophage polarization through MAPK signaling pathway
- Therapeutic Effect of Tetrapanax papyriferus and Hederagenin on Chronic Neuropathic Pain of Chronic Constriction Injury of Sciatic Nerve Rats Based on KEGG Pathway Prediction and Experimental Verification
- Essential Oil From Tetrapanax papyrifer (Hook.) K. Koch: Chemical Composition, Antioxidant Activity, α-Glucosidase Inhibitory Effect Integrating Molecular Docking Analysis
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Medulla Tetrapanacis water extract alleviates inflammation and infection by regulating macrophage polarization through MAPK signaling pathway
The only pharmacology study located that is explicitly on this plant part. A water extract of Medulla Tetrapanacis, profiled by UPLC-Orbitrap mass spectrometry to eight abundant compounds, suppressed lipopolysaccharide-induced nitric oxide, tumour necrosis factor alpha and interleukin 6 in RAW 264.7 macrophages, shifted macrophage polarisation toward an anti-inflammatory phenotype, blocked MAPK activation and inhibited Staphylococcus aureus growth. Notably it also reduced the phagocytic capacity of the macrophages against S. aureus, which is a caution rather than a benefit. Cell culture only, with no animal or human data, and the authors frame it against the drug's traditional use for lactation and mastitis.
Therapeutic Effect of Tetrapanax papyriferus and Hederagenin on Chronic Neuropathic Pain of Chronic Constriction Injury of Sciatic Nerve Rats Based on KEGG Pathway Prediction and Experimental Verification
Forty-two rats with chronic constriction injury of the sciatic nerve received the crude drug, hederagenin, pregabalin or mecobalamin by mouth. Both the crude drug and hederagenin reduced mechanical, thermal and cold hypersensitivity and lowered dorsal root ganglion TRPM8, TRPA1, TRPV1, TRPV4 and phosphorylated p38 MAPK; the crude drug also lowered serum interleukin 1 beta, interleukin 6 and tumour necrosis factor alpha. The paper treats the material as the Tetrapanax component of Danggui Sini decoction, that is the pith, but does not state the plant part explicitly. The DOI resolves and the record carries no retraction or expression of concern as of this writing, but the journal has a large retraction history and the result should be weighted accordingly.
Essential Oil From Tetrapanax papyrifer (Hook.) K. Koch: Chemical Composition, Antioxidant Activity, α-Glucosidase Inhibitory Effect Integrating Molecular Docking Analysis
Sixty-one volatile compounds were identified in an essential oil of this species, dominated by sesquiterpene hydrocarbons at about 96 percent, with beta-cubebene, caryophyllene and alpha-cubebene the largest. Antioxidant activity was weak (DPPH IC50 about 723 micrograms per millilitre) and alpha-glucosidase inhibition was about 18 percent at 500 micrograms per millilitre. Included with the caveat that the paper does not identify the plant part distilled, so it cannot be assumed to characterise the medicinal pith.
Historical Texts
Ben Cao Gang Mu, Li Shizhen
Ming dynasty, 1596Chinese materia medica of the Tang period onward, under the name tong tuo mu
Tang dynasty, 8th century onwardYin Pian Xin Can
Republican China, 1935Pharmacopoeia of the People's Republic of China
Current editionsReferences
- Quan L, Shi X, Zhang J, Shu Z, Zhou L. Preparation of a Novel Lignocellulose-Based Aerogel by Partially Dissolving Medulla Tetrapanacis via Ionic Liquid . Gels (2024) [DOI]
- Zhang J, Ji H, Liu Z, Zhang L, Wang Z, Guan Y, Gao H. 3D Porous Structure-Inspired Lignocellulosic Biosorbent of Medulla tetrapanacis for Efficient Adsorption of Cationic Dyes . Molecules (2022) [DOI]
- Yu Z, Liang X, Guo S, Zhang P. Chloroplast genome sequencing and phylogenetic analysis of Tetrapanax papyrifer (Hook.) K. Koch (Araliaceae) . Mitochondrial DNA Part B (2026) [DOI]
- Zhong Yao Da Ci Dian (Dictionary of Chinese Materia Medica) editorial board. Geng Tong Cao: the woody stem core of Aeschynomene indica L., source text Yin Pian Xin Can . Zhong Yao Da Ci Dian, entry reproduced at zhongyaocai360
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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