Yu Li Ren
StarPrunus humilis Bge., Prunus japonica Thunb., Prunus pedunculata Maxim.
Traditionally used for
- Digestion
- Bowel health
- Urinary & fluids
- Menstrual & women's health
Cautions & contraindications
- Pregnancy
- Young children
☯ TCM Properties
Moistens the Intestines and Unblocks the Bowels; Promotes Urination and Reduces Edema; Descends Qi and Relieves Distension; Moistens Dryness
Traditional Chinese Uses
Yu Li Ren (郁李仁) is the kernel of Prunus humilis Bge., P. japonica Thunb. and P. pedunculata Maxim. (Rosaceae), Semen Pruni. It is acrid, bitter and sweet and neutral, entering the Spleen, Large Intestine and Small Intestine channels. It moistens the Intestines and unblocks the bowels, promotes urination and reduces oedema, and descends Qi to relieve distension.
It is the moistening laxative chosen when constipation is accompanied by Qi stagnation — dry, difficult stool together with abdominal distension and fullness — because unlike the purely oily seeds it also moves Qi downward. It is gentler than the purgatives and suits constipation in the postpartum period, in the elderly and in the weak. Its diuretic action is used for oedema, particularly swelling of the legs, and for abdominal fullness from retained fluid.
It is contraindicated in pregnancy, and is used with care where the stools are already loose or the fluids depleted.
Western Herbalism Properties
Relationships
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Botanical Description
Yu Li Ren is the dried seed of several closely related Prunus species in the Rosaceae family, principally Prunus humilis Bunge, Prunus japonica Thunb., and Prunus pedunculata (Pall.) Maxim. These are small deciduous shrubs, generally 0.5 to 2 meters tall, with slender ascending branches and grayish-brown bark. The leaves are alternate, ovate to oblong-lanceolate, 2 to 6 centimeters long, with finely serrate margins and short petioles. Showy solitary or paired flowers appear in spring before or with the leaves, bearing five white to pale pink petals and numerous stamens. The drupes are globose, about 1 to 1.5 centimeters in diameter, ripening red to dark red, each enclosing a single hard stone. The kernels within these stones, oily and bittersweet, are the Yu Li Ren of commerce, harvested in summer, freed from the hard endocarp, and stored carefully to prevent rancidity. Native to northern China, Korea, Mongolia, and adjacent regions.
Active Constituents
Multiflorin A
Acetylated flavonol glycosideConcentration: concentrated in the seed coat; proposed as the quality-control marker for Pruni Semen and much higher in the small-seeded P. humilis and P. japonica than in the large-seeded material
The principal purgative constituent of the drug and the reason Yu Li Ren does not behave like an anthraquinone laxative. At 20 mg/kg it caused watery diarrhoea in over half of treated mice. It downregulates sodium-glucose cotransporter 1, occludin and claudin 1 in the small intestine, inhibiting glucose absorption and creating a hyperosmotic lumen, and upregulates aquaporin 3 to promote water secretion. The acetyl group is the active moiety.
Amygdalin
Cyanogenic diglycosideConcentration: located in the kernel; reported at roughly 18 mg/g in P. humilis and P. japonica seed against roughly 31 mg/g in the large-seeded material including the P. salicina adulterant
Hydrolysed by gut microbial beta-glucosidase to release hydrogen cyanide, which is why oral amygdalin is far more toxic than parenteral. It is the constituent that makes dose discipline matter with Yu Li Ren, and the roughly two-fold higher content in large-seeded material means a substituted batch delivers substantially more cyanogenic load at the same weight.
Afzelin (kaempferol 3-O-rhamnoside)
Flavonol glycosideConcentration: distributed in the seed coat rather than the kernel
One of the seed-coat flavonoids characteristic of authentic small-seeded Pruni Semen. A seed-coat flavonoid fraction from Cerasus humilis (a synonym of Prunus humilis) relieved constipation in mice through AQP3/AQP4 and c-Kit/SCF signalling, indicating the flavonoids act on both water handling and interstitial-cell-driven motility.
Kaempferitrin (kaempferol 3,7-di-O-rhamnoside)
Flavonol glycosideConcentration: distributed in the seed coat
A second characteristic seed-coat flavonol glycoside of Pruni Semen. Its abundance, with afzelin and multiflorin A, is what distinguishes the authentic small-seeded drug from the amygdalin-rich large-seeded material and adulterants.
Prunuside
GlycosideIsolated in 1975 from Prunus japonica as a purgative constituent of the seed, and the first such principle characterised from this drug. It predates and complements the modern identification of multiflorin A as the main purgative agent.
Fixed seed oil
Triacylglycerol fixed oilConcentration: the bulk of the kernel; reported fatty acids include palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, arachidic and cis-11-eicosenoic acids
The lubricating fraction behind the classical action of moistening the intestines. Semen Pruni oil attenuated loperamide-induced constipation in mice, with effects on enteric neurotransmitters, oxidative stress and inflammatory markers, so the oil is not merely an inert vehicle for the flavonoids.
⚠ Drug Interactions
Adulterant Prunus species sold as Pruni Semen (P. salicina, P. tomentosa, P. avium)
DNA barcoding, morphology and chemical profiling of 37 market, field and plantation samples of Pruni Semen found that there was almost no authentic material on the market. Samples split into big seed (P. pedunculata and the adulterant P. salicina) and small seed (P. humilis, P. japonica and the adulterants P. tomentosa and P. avium). Small seeds were rich in flavonoids and low in amygdalin; big seeds were the reverse, with amygdalin reported at roughly 31 mg/g against roughly 18 mg/g. Since multiflorin A carries the purgative action and amygdalin carries the toxicity, the substitution moves both in the wrong direction.
Clinical note: Do not treat this drug as commodity material. Require species-level identification, ideally DNA-based, and be aware that P. pedunculata is itself an official source species but chemically closer to the adulterants than to P. humilis and P. japonica. If a batch fails to purge at the usual dose, suspect substitution rather than simply escalating the dose.
Other cyanogenic kernel drugs and foods (Ku Xing Ren / Prunus armeniaca, Tao Ren / Prunus persica, flaxseed, bitter almond, cassava)
Amygdalin in Yu Li Ren is hydrolysed by intestinal microbial beta-glucosidase to release hydrogen cyanide. That release is a function of total oral amygdalin and related cyanogenic glycoside intake, so stacking several kernel drugs in one prescription, or in a prescription plus the diet, sums the exposure. The risk is greatest with large-seeded or adulterated Yu Li Ren, which carries roughly twice the amygdalin.
Clinical note: Count all cyanogenic kernels in a formula together rather than dosing each to its own maximum. Avoid combining Yu Li Ren with Ku Xing Ren and Tao Ren at full dose, and ask about bitter almond and cassava in the diet. Do not exceed Pharmacopoeia dosage, and avoid in children.
Antidiabetic drugs and SGLT inhibitors
Multiflorin A lowers peak postprandial glucose in mice, and the glucose-lowering runs synchronously with the purgative action; mechanistically it downregulates intestinal sodium-glucose cotransporter 1, which is the same transporter family targeted by SGLT inhibitors. This is a mouse finding at a purgative dose and has not been tested in humans, but it means the herb's glucose effect and its laxative effect cannot be separated.
Clinical note: No specific precaution is established. In a diabetic patient on an SGLT inhibitor who develops diarrhoea on this herb, consider the shared intestinal mechanism rather than assuming an unrelated gastrointestinal upset.
Digoxin, loop and thiazide diuretics, and other laxatives
The therapeutic effect of the drug is osmotic and secretory diarrhoea driven by inhibited glucose absorption, increased intestinal permeability and upregulated aquaporin 3. Any watery stool of this kind carries obligate fluid and electrolyte loss, and the herb is also classically used to promote urination and reduce oedema, compounding the fluid shift.
Clinical note: Avoid in patients on digoxin or high-dose diuretics. Keep courses short, ensure adequate fluid intake, and do not combine with other purgatives. Contraindicated in pregnancy and in patients who are already fluid- or Yin-depleted.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 6–10 g | Daily | — | — | 中国药典 2020 【用法与用量】6～10g。 【注意】孕妇慎用。 【性味与归经】辛、苦、甘，平。归脾、大肠、小肠经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
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
1 verified · 2 unverified
Show 3 studies
- A novel purgative mechanism of multiflorin A involves changing intestinal glucose absorption and permeability
- Semen Pruni oil attenuates loperamide-induced constipation in mice by regulating neurotransmitters, oxidative stress and inflammatory response
- Flavonoids from Cerasus humilis seed coat alleviate constipation in mice: Role of AQP3/4 and c-Kit/SCF signaling pathways
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
A novel purgative mechanism of multiflorin A involves changing intestinal glucose absorption and permeability
Multiflorin A at 20 mg/kg induced watery diarrhoea in over half of treated mice, and its lowering of peak postprandial glucose was synchronous with the purgative action, with the acetyl group identified as the active moiety. It was metabolised chiefly in the small intestine, where it decreased sodium-glucose cotransporter 1, occludin and claudin 1, inhibiting glucose absorption and producing a hyperosmotic lumen, and increased aquaporin 3 to promote water secretion. Unabsorbed glucose reshaped the colonic microbiota, and the resulting gas and organic acids promoted defecation. Permeability and glucose absorption recovered afterwards, with an increase in Bifidobacterium. This is the first systematic experimental study of the purgative effect of the drug's main active constituent.
Semen Pruni oil attenuates loperamide-induced constipation in mice by regulating neurotransmitters, oxidative stress and inflammatory response
The fixed oil of Pruni Semen relieved loperamide-induced constipation in mice, acting on enteric neurotransmitters, oxidative stress markers and inflammatory mediators rather than through simple lubrication. It shows that the oily kernel fraction contributes pharmacologically to the classical moistening action and is not merely a vehicle for the seed-coat flavonoids.
Flavonoids from Cerasus humilis seed coat alleviate constipation in mice: Role of AQP3/4 and c-Kit/SCF signaling pathways
A flavonoid fraction from the seed coat of Cerasus humilis, a synonym of Prunus humilis and one of the three official source species, relieved constipation in mice through aquaporin 3 and 4 and c-Kit/SCF signalling. This is species-specific evidence for P. humilis rather than for Pruni Semen in general, and it locates the activity in the seed coat, the same tissue in which the flavonoids and multiflorin A are concentrated and which is lost when kernels are dehulled.
⚠ Safety & Contraindications
- Pregnancy
- Young children
Contraindications
Its use is cautious in pregnant women.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, p. 94.
Historical Texts
Shen Nong Ben Cao Jing
Han dynastyYao Xing Lun
Tang dynasty, seventh centuryBen Cao Gang Mu
Ming dynasty, 1596References
- Li P, Zhao Z, Li Z, Zeng R, Li W. Distinguishing features of Prunus humilis, P. japonica, P. pedunculata seeds and their adulterant based on DNA barcoding, morphological characterization, and chemical profiles . Fitoterapia (2024) [DOI]
- Oshio H, Miyamoto M, Sanno Y, Kase Y. Studies on a New Purgative Constituent of Prunus japonica THUNB., Prunuside . YAKUGAKU ZASSHI (1975) [DOI]
- Oku H, Abe M, Maruyama K, Yagi T, Ishiguro K. Mechanism of the purgative action of multiflorin A . Planta Medica (2014) [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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