Qian Niu Zi
StarPharbitis nil (L.) Choisy; Pharbitis purpurea (L.) Voigt
Traditionally used for
- Cough & breathing
- Digestion
- Bowel health
- Urinary & fluids
Cautions & contraindications
- Pregnancy
- Young children
- Toxic — professional use only
☯ TCM Properties
Drains Water and Reduces Edema; Purges Heat and Unblocks the Bowels; Resolves Phlegm-Fluid Retention; Kills parasites and resolves accumulation
Traditional Chinese Uses
Qian Niu Zi (牵牛子) is the seed of Pharbitis nil (L.) Choisy and P. purpurea (Convolvulaceae), Semen Pharbitidis; the black and the pale seeds are used alike. It is bitter and acrid and cold and toxic, entering the Lung, Kidney and Large Intestine channels. It drains Water and reduces oedema, purges Heat and unblocks the bowels, resolves Phlegm-Fluid retention, and kills parasites to resolve accumulation.
It is used for oedema and abdominal fullness from retained fluid, for constipation with Heat accumulation, for Phlegm-Fluid lodged in the chest with wheezing and cough, and for roundworm and tapeworm infestation with abdominal pain and food accumulation. It moves water out through both stool and urine.
It is toxic and drastically purging. It is contraindicated in pregnancy and in the weak or deficient, is not combined with Ba Dou, and is dosed sparingly — powdered it is markedly stronger than decocted. Overdose produces violent purgation, abdominal pain, vomiting, haematuria and central nervous system effects.
Relationships
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Botanical Description
Pharbitis nil (syn. Ipomoea nil), Japanese morning glory, is an annual twining vine in the Convolvulaceae family, climbing 2-3 m by means of slender stems clothed with retrorse hairs. The leaves are alternate, broadly ovate to three-lobed, 7-15 cm across, cordate at the base, and softly hairy on both surfaces. The showy funnel-shaped flowers, 5-8 cm across, open in the early morning and may be blue, purple, pink, red, or white, often with a paler throat; they are borne singly or in small axillary cymes on long peduncles. The fruit is a globose capsule about 1 cm in diameter enclosing three to six trigonous, hard, black or pale (Pharbitis purpurea-type) seeds. Qian Niu Zi is the dried mature seed (POWO; Wikipedia).
Active Constituents
Pharbitin
Resin glycoside (ether-insoluble glycoresin fraction)The purgative principle of the seed and, on current evidence, also its toxic principle - the two are not separable. Alkaline hydrolysis yields the glycosidic acid pharbitic acid together with nilic, tiglic, (+)-2-methylbutyric and valeric acids. Pharbitin raises the tone of isolated mouse colon concentration-dependently through acetylcholine receptors while lowering ileal tension, which is a coherent mechanism for a drastic lower-bowel purgative. It also has anthelmintic activity, reported to act on the nicotinic acetylcholine receptor subunit UNC-63.
Chlorogenic acid
Hydroxycinnamic acid ester (phenylpropanoid)One of the phenolic acids of the seed, and a marker whose level shifts measurably during the traditional stir-frying process used to soften the drug's harshness.
Caffeic acid and its derivatives
Hydroxycinnamic acid (phenylpropanoid)Nine caffeic acid derivatives have been isolated from the seeds. This phenolic fraction, rather than the resin glycosides, is credited with the antioxidant and anti-inflammatory activity reported for seed extracts, and is used as a processing marker.
ent-Kaurane diterpenoids and diterpene glycosides
DiterpenoidA structurally distinct group isolated from the seeds, unrelated to the purgative resin fraction. Their pharmacology in humans is not established.
Fixed oil and fatty acids
Triacylglycerols and free fatty acidsThe seed's lipid fraction, rich in linoleic acid. It contributes bulk rather than the drug action, but it is the fraction most altered by stir-frying, which drives transesterification and is part of why processed seed is milder than raw.
⚠ Drug Interactions
Digoxin and other cardiac glycosides
Qian Niu Zi is a drastic purgative graded as toxic in the Chinese Pharmacopoeia, and at the higher end of its 3-9 g range it produces powerful, watery evacuation. Any drastic purgative carries the classic risk of potassium and fluid loss, and hypokalaemia sensitises the myocardium to digoxin. There are no published case reports specific to this herb; the reasoning is from its established purgative pharmacology.
Clinical note: Avoid in patients on digoxin. If purgation has already occurred, check potassium before resuming or adjusting the glycoside.
Loop and thiazide diuretics, and corticosteroids
The herb is used precisely to drain water and reduce oedema, so its intended effect overlaps with that of a diuretic; combined with the fluid loss of purgation, the two are additive on volume and electrolytes. Corticosteroids independently promote potassium loss. No clinical study has quantified this for Pharbitidis Semen.
Clinical note: Do not stack this herb on top of an established diuretic regimen in a frail or elderly patient. Monitor for postural dizziness, cramps and weakness.
Orally administered drugs generally (especially modified-release and narrow-therapeutic-index formulations)
Pharbitin concentration-dependently increases colonic tone, and the herb's clinical effect is accelerated transit and evacuation. Shortened intestinal residence time reduces the window for dissolution and absorption, which matters most for modified-release preparations and drugs with narrow therapeutic windows. This is a general property of drastic purgatives rather than a herb-specific published finding.
Clinical note: Separate oral medication from the herb by several hours, and be alert to loss of effect in patients on oral contraceptives, anticonvulsants or thyroid replacement.
Ba Dou (Croton tiglium) and other stimulant purgatives
The classical Nineteen Mutual Fears (shi jiu wei) explicitly names Qian Niu Zi as incompatible with Ba Dou, and both are drastic purgatives in the toxic grade. On modern pharmacological grounds the combination is straightforwardly additive on gastrointestinal irritation. Reported signs of Qian Niu Zi overdose include severe abdominal pain, vomiting, haematuria, and mucus and blood in the stool, with neurological symptoms at extreme doses; overdose has also been linked to kidney damage, and network analysis of the processed drug's marker components implicates nephritis-related pathways.
Clinical note: Never combine these two herbs. Keep Qian Niu Zi within 3-9 g in decoction, or 1.5-3 g when given as powder or pill, where the resin glycosides are not diluted by extraction. Use stir-fried rather than raw seed to moderate the action, and do not prescribe it long-term.
Uterotonic and abortifacient drugs (e.g. misoprostol, oxytocin)
Qian Niu Zi is absolutely contraindicated in pregnancy in the Chinese Pharmacopoeia and appears on the standard lists of pregnancy-contraindicated Chinese medicines, on the grounds that drastic purgation and reflex uterine stimulation can provoke miscarriage. This is a contraindication carried on traditional and regulatory authority rather than on a controlled study.
Clinical note: Do not prescribe in pregnancy or to women trying to conceive. Also avoid in Spleen and Stomach deficiency, in constitutional weakness without a true excess pattern, and in children.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 3–6 g | — | — | — | ChP 2025. In pills or powder, 1.5–3 g per dose. Contraindicated in pregnancy; NOT combined with Ba Dou or Ba Dou Shuang. Corrected from a generic 6-15g decoction filler value generated from tcm_category. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Expelling water downward while warming and moving qi in the lower burner, so fluid is drained without cold stagnation remaining.
Edema and hernia-like disorders from water and qi stagnation. Qian Niu Zi is toxic, contraindicated in pregnancy and incompatible with Ba Dou (nineteen antagonisms).
Core pair of a classical formula — Yu Gong San, Ru Men Shi Qin (Zhang Congzheng)
Evidence Tier
Moderate evidence · 5 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
5
1 verified · 4 unverified
Show 5 studies
- Different effects on the tonus of colon and ileum isolated from mouse by resin glycoside (pharbitin) of Pharbitidis Semen
- Bioassay-Guided Isolation of Anthelmintic Components from Semen pharbitidis, and the Mechanism of Action of Pharbitin
- Dynamic changes in marker components during the stir-frying of Pharbitidis Semen, and network analysis of its potential effects on nephritis
- Ethanol extract of Pharbitis nil ameliorates liver fibrosis through regulation of the TGF β1-SMAD2/3 pathway
- A Purified Resin Glycoside Fraction from Pharbitidis Semen Induces Paraptosis by Activating Chloride Intracellular Channel-1 in Human Colon Cancer Cells
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
Different effects on the tonus of colon and ileum isolated from mouse by resin glycoside (pharbitin) of Pharbitidis Semen
Isolated-tissue study showing that pharbitin raises the tone of mouse colon concentration-dependently via acetylcholine receptors while decreasing ileal tension. This regional selectivity gives a mechanism for the herb's action as a large-bowel purgative rather than a general gut stimulant.
Bioassay-Guided Isolation of Anthelmintic Components from Semen pharbitidis, and the Mechanism of Action of Pharbitin
Bioassay-guided fractionation identified pharbitin as the anthelmintic principle of the seed, with an IC50 of about 41 microg/mL, and traced its action to the nicotinic acetylcholine receptor subunit UNC-63 in Caenorhabditis elegans. This supports the traditional indication of killing parasites and gives it a defined molecular target.
Dynamic changes in marker components during the stir-frying of Pharbitidis Semen, and network analysis of its potential effects on nephritis
Tracked how marker constituents shift during the traditional stir-frying of the seed, finding transesterification of the lipid fraction, and used network analysis to link the phenolic acid components to nephritis-related pathways including AGE-RAGE and TNF signalling. Relevant to why processed seed is preferred clinically over raw.
Ethanol extract of Pharbitis nil ameliorates liver fibrosis through regulation of the TGF β1-SMAD2/3 pathway
An ethanol extract of the seed reduced liver fibrosis in an animal model by downregulating TGF-beta1-induced SMAD2/3 signalling. A preclinical finding well outside the herb's traditional indications; it does not translate into a clinical recommendation.
A Purified Resin Glycoside Fraction from Pharbitidis Semen Induces Paraptosis by Activating Chloride Intracellular Channel-1 in Human Colon Cancer Cells
The purified resin glycoside fraction killed human colon cancer cells by paraptosis, a non-apoptotic form of cell death, through activation of chloride intracellular channel-1. Useful as a demonstration that the resin glycosides are broadly cytotoxic, which bears on the herb's toxicity as much as on any antitumour potential.
⚠ Safety & Contraindications
- Pregnancy
- Young children
- Toxic — professional use only
Contraindications
Contraindicated in pregnancy and in the weak or depleted.
Safety Warnings
- A drastic purgative for short-term use only.
- Incompatible with Ba Dou under the classical nineteen antagonisms.
⚠ Toxicity Information
Severe watery diarrhoea, abdominal colic and vomiting; in overdose, haematuria, and neurological signs including speech disturbance.
Historical Texts
Ming Yi Bie Lu
Six Dynasties, c. 500 CE (attributed to Tao Hongjing)Shi Jiu Wei (the Nineteen Mutual Fears)
Traditional pharmacological doctrine, systematised by the Jin-Yuan periodPharmacopoeia of the People's Republic of China
Modern (current edition)References
- Gao P, Wang L, Chen X, Yang X, Chen K, Yue R, Wu H, Jiang Y, Wu H, Tang J, Wang T. Pharbitidis Semen: A review of botany, traditional uses, phytochemistry, pharmacology, and toxicology . Journal of Ethnopharmacology (2023) [DOI]
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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