Cleavers (Galium aparine L.): A Comprehensive Reference
1. Identity and Botanical Characterization
Taxonomic Identity
Galium aparine L., with common names including cleavers, clivers, catchweed, robin-run-the-hedge, goosegrass, and sticky willy, is an annual, herbaceous plant of the family Rubiaceae. Additional recorded English common names include sweetheart, hitchhikers, bedstraw, stickyweed, sticky bob, stickybud, stickyback, sticky molly, stickyjack, stickeljack, grip grass, sticky grass, bobby buttons, whippysticks, and velcro plant.
The genus name Galium is Dioscorides' name for the plant, derived from the Greek word for milk, because the flowers of Galium verum were used to curdle milk in cheese making. The species epithet aparine was used by Theophrastus and means "clinging" or "seizing," derived from the Greek apairo, itself from apo ("from") + airo ("to lift").
The unusual common name "cleavers" comes from the plant's most identifying feature: the fact that it sticks (or cleaves) to clothing and even skin by way of tiny hairs along the stem and seed pods. Cleavers belongs to the same family as coffee (Rubiaceae).
Botanical Description and Distribution
Galium aparine is a straggling, square-stemmed annual growing to 4 feet, with whorls of lance-shaped leaves, clusters of small white flowers, and small, round, green fruit bearing hooked prickles. This trailing annual plant produces square, weak stems that can reach up to 1 metre long. Tiny hooked hairs on the stem and leaves give it a burr-like texture, allowing it to cling to animals and humans for seed dispersal.
Galium aparine is an annual herbaceous plant native to Europe, North Africa, and Asia, belonging to the Rubiaceae family, and is commonly found worldwide as a weed in temperate regions. Its habitat in the north reaches Alaska and Greenland, and as an introduced species it can also be found in Australia, New Zealand, and sub-Antarctic islands.
Parts Used and Common Preparations
The above-ground fresh plant is most commonly used, and sometimes the dried herb. The primary preparations include cold infusion, fresh juice (succus), and tincture. The plant parts used medicinally include the whole plant, with particular emphasis on the stems and leaves. The stems — covered in tiny hooked hairs — are most commonly used due to their high concentration of active compounds. The leaves are also harvested and used, often dried and ground into a powder for various preparations. The roots are occasionally used but are less prominent in traditional applications. The entire plant is typically harvested during the flowering period for optimal potency.
The whole plant — stems, leaves, and flowers — is harvested during flowering season and processed using hydroalcoholic, ethanolic, or methanolic extraction methods to produce medicinal extracts rich in polyphenols and flavonoids. The fruits of cleavers can be collected, dried, and roasted for use as a coffee substitute.
Aerial parts, or the top third of the plant, are typically collected in spring and early summer — May and June — when just coming into flower. Cleavers is traditionally prepared as a fresh juice or tea, which preserves water-soluble compounds like flavonoids and tannins. Dried herb infusions and standardized extracts are also available; the choice depends on convenience and intended use, though whole-herb or aqueous preparations may retain a broader spectrum of active constituents compared to isolated extracts.
2. Traditional and Historical Use
Classical Antiquity
In classical texts, such as those by Dioscorides, G. aparine is mentioned as a remedy for burns, hemorrhages, and other medicinal uses. Andrés Laguna, in his commentary on Dioscorides, noted its ability to staunch blood flow. According to Maud Grieve, Dioscorides recorded that Greek shepherds of his day employed the stems of this herb to make a rough sieve, a tradition later reported by Linnaeus as still practiced in Sweden as a filter for straining milk.
Galium aparine appears in herbal texts dating back to Roman naturalist Pliny the Elder, who noted its use as a spring tonic. John Gerard (writing in the late 16th century) recommended clivers as "a marvellous remedy for the bites of snakes, spiders and all venomous creatures," and, quoting Pliny, suggested that a pottage made of clivers, mutton, and oatmeal was good to prevent fatness.
Dioscorides also described an ointment made from the expressed juice of the plant mixed with hog's lard as being of great efficacy for treating tumours of the breast.
Medieval and Early Modern Europe
Medieval European herbals called it "cleaverwort" and recommended it for skin ailments and general detoxification. Many of the most renowned herbalists and physicians throughout history referenced this herb's use for hot, inflamed skin conditions and as a blood purifier. Culpeper additionally recommended cleavers for the treatment of earache.
G. aparine has been a cornerstone of European, Native American, and Traditional Chinese Medicine for centuries, primarily lauded for its efficacy as a diuretic, depurative (cleansing), and lymphatic tonic. Poultices and washes made from cleavers were traditionally used to treat a variety of skin ailments, light wounds, and burns. As a pulp, it was used to relieve venomous bites and stings.
In Europe, the plant's dried, matted foliage was once used to stuff mattresses. Several of the bedstraws were used for this purpose because the clinging hairs cause the branches to stick together, enabling the mattress filling to maintain a uniform thickness.
Native American Traditions
Cleavers was used as a love medicine by American First Nations; an infusion was used as a bath by women to be successful in love. Several Native American tribes used an infusion of the plant for gonorrhea. In some Native American cultures, cleavers are also known as "deer medicine," as deer are said to sleep or give birth in clumps of the herb, and it is considered a birthing remedy in that tradition.
19th-Century and Eclectic Traditions
In England's 19th-century folk medicine, women prepared water infusions of cleavers to relieve mastitis, tying the warmed herb poultice around the breast. Galium aparine was historically used to treat ulcers and nodular growths of the skin and mucous membranes that could be found on or under the skin. It was first reported in published literature to be effective in treating ulcers in 1883.
Galium has a long history of use in folk medicine as a spring alterative and kidney tonic. Dietary supplements and galenic remedies containing G. aparine extract are recommended as immunomodulatory, anti-inflammatory, and for detoxification, as well as for the improvement of the functioning of the lymphatic and blood circulatory systems.
3. Key Chemical Constituents
Chemical constituents of Galium aparine include: iridoid glycosides such as asperulosidic acid and 10-deacetylasperulosidic acid; asperuloside; monotropein; aucubin; alkaloids such as caffeine; flavonoids; coumarins; organic acids such as citric acid and a red dye; phenolics such as phenolic acid; and anthraquinone derivatives such as the aldehyde nordamnacanthal (1,3-dihydroxy-anthraquinone-2-al).
More detailed phytochemical research using UHPLC-DAD-MS/MS analysis has revealed that G. aparine herb contains iridoids (asperulosidic acid, 10-deacetylasperulosidic acid, monotropein, asperuloside, aucubin); alkaloids (protopine, harmine, and related compounds); phenolcarbonic and hydroxycinnamic acids (chlorogenic, caffeic, n-coumaric, ferulic, caftaric, and gentisic acids); flavonoids (quercetin, dihydroquercetin, rutin, hyperoside, isoquercitrin, kaempferol, kaempferol-3-O-glucoside (astragalin), epicatechin, neohesperidin, luteolin, luteolin-7-O-diglucoside, and apigenin); and phytosterols including cholesterol, campesterol, stigmasterol, and sitosterol.
Specific named constituents documented in the aerial parts include: caffeic, gallic, salicylic, and citric acids; iridoid glycosides (asperuloside); tannins (gallotannic acid); coumarins; flavonoids; polyphenolic acids; and alkanes, with anthraquinones being present primarily in the root.
Qualitative phytochemical screening has confirmed the secondary metabolite composition of the plant extract to be rich, demonstrating high levels of flavonoids, phenols, tannins, as well as a notable concentration of alkaloids, glycosides, and saponins.
The aerial parts contain polysaccharides that may contribute to immunomodulatory activity. Silica content is relatively high compared to many herbs, supporting traditional use for connective tissue. Caffeic acid derivatives have been identified as contributors to antioxidant capacity.
Iridoid glycosides, including asperuloside, are considered mildly laxative and purgative. Coumarins present in Galium species function as natural blood thinners and promote lymphatic drainage.
The high concentrations of flavonoids, phenols, and tannins in G. aparine confirm a substantial antioxidant capacity, which is relevant to conditions in which oxidative stress plays a pathogenic role.
4. Proposed Mechanisms of Action
Studies have confirmed the use of this plant as antimicrobial, antioxidant, and immunomodulatory, attributing these effects to the presence of flavonoids, polyphenols, and hydroxycinnamic acid derivatives.
Regarding its immunomodulatory potential, research identifying the mechanism of action has shown that G. aparine herb contains bioactive fractions made of a polysaccharide complex, pectin complex, and polyphenolic complex that stimulate the activity of immunocompetent blood cells and increase the percentage of proliferation of lymphocytes in the lymphocyte blast transformation model.
Mechanistically, the diuretic effect may stem from tubule modulation in the kidneys, encouraging sodium and water excretion. The astringent tannins can tighten mucosal tissues, which may explain its use for mild skin irritations or lymphatic stagnation. Iridoids are rapidly metabolized in vivo to active forms that interact with macrophage cells.
Iridoids isolated from Galium species have been found to possess anti-inflammatory, cardiovascular, and antitumor activities. According to Robert et al. (2004), Galium species are believed to have mild diuretic effects, which may reduce kidney stone formation by increasing urinary flow and volume.
5. Scientific Evidence by Area of Use
5.1 Immunomodulatory Activity
As part of folk remedies and dietary supplements, G. aparine herb has been studied for its immunomodulatory properties. One study analyzed the chemical composition and immunomodulatory activities of ethanolic extracts obtained by maceration with 20%, 60%, or 96% ethanol. Hydroxycinnamic acid derivatives, flavonoids, and polyphenols were determined spectrophotometrically, with extractives and polysaccharides quantified gravimetrically. Qualitative composition was studied using UHPLC-DAD-MS/MS analysis, and immunomodulatory activity was assessed in a lymphocyte blast transformation reaction.
All ethanolic extracts stimulated the transformational activity of immunocompetent blood cells, with the 96% ethanolic extract being the most active. The authors concluded that the data necessitate further research into the mechanisms of immunomodulatory activity.
A separate study investigating the immunomodulatory potential of G. aparine (GAE) used an animal model of cyclophosphamide-induced immunosuppression. Animals were categorized into five groups: normal, cyclophosphamide-only, and three groups receiving cyclophosphamide plus GAE at 5 µg, 50 µg, or 500 µg. The cyclophosphamide group showed significantly reduced spleen weights compared to the normal group, while GAE-treated groups displayed a dose-dependent increase in spleen weight. GAE also demonstrated dose-dependent enhancement of splenocyte proliferating activity, with significant increases in both LPS- and ConA-induced assays. NK cell activity significantly increased in the GA50 and GA500 groups. Cytokine analysis revealed significant increases in IL-6, TNF-α, and IFN-γ levels in ConA-induced splenocytes treated with GAE.
Evidence strength: Studies on G. aparine water extracts remain insufficient, and specific findings regarding cellular mechanisms, gene profiles, and physiological activities related to immune function through animal experiments are limited. All immunomodulatory evidence to date is preclinical (in vitro and animal); no human clinical trials have been conducted.
5.2 Antioxidant Activity
Laboratory studies have demonstrated the antioxidant property and radical scavenging capability of G. aparine extract. The highest antioxidant activity was observed at 200 mg/ml, and at lower concentrations, radical scavenging occurred in a dose-dependent manner. Antioxidant activity was confirmed by DPPH radical scavenging assay.
Antioxidant activity and radical scavenging capability of G. aparine extract have been confirmed, though ascorbic acid exhibited higher radical scavenging activity at all concentrations tested.
Evidence strength: Antioxidant evidence is confined to in vitro assays. No human studies have evaluated antioxidant endpoints attributable to cleavers supplementation.
5.3 Antimicrobial Activity
Previous studies have confirmed antimicrobial effects of different extracts from G. aparine. The insect antifeedant anthraquinone aldehyde nordamnacanthal (1,3-dihydroxy-anthraquinone-2-al) was isolated from Galium aparine. In antibacterial screening, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi were significantly susceptible to extracts and fractions, with MICs ranging from 0.12 to 200 mg/mL.
Evidence strength: All antimicrobial data is from in vitro assays. No clinical trials in humans have been conducted to verify these effects.
5.4 Wound Healing
In traditional medicine, G. aparine has been one of the widespread plants used for treating different injuries or skin afflictions. Previously reported chemical compounds of GA suggested therapeutic effects for wound healing, yet its regulatory effects on the cellular and molecular stages of the wound healing process had not been fully investigated.
A 2024 study (BMC Complementary Medicine and Therapies, published July 23, 2024, DOI: 10.1186/s12906-024-04355-y) showed that the viability assay found no cytotoxic effects on human umbilical endothelial cells (HUVEC) and normal human dermal fibroblasts (NHDF) treated with different concentrations of whole plant extract; cell viability increased in a dose-dependent manner. The scratch assay showed improved cell migration and wound closure. The authors concluded that the study demonstrates anti-oxidant, anti-microbial, and in vitro wound-healing effects of the GA hydroalcoholic extract, which aligns with its use in traditional medicine.
The results from that study are proposed as a basis for further investigations using animal models and expanded phytochemical studies, with the authors noting that further evaluation of effects on angiogenesis and cell proliferation signaling pathways could provide novel insights.
Evidence strength: Preliminary. Evidence is from a single in vitro study using human cell lines (HUVEC and NHDF). No animal or human clinical trials have confirmed wound-healing efficacy.
5.5 Anticancer / Antiproliferative Activity
Galium species have been traditionally used for their anti-cancer and antioxidant effects in folk medicine. One study aimed to investigate the potential anti-proliferative and apoptotic effect of G. aparine methanol (MeOH) extract on MCF-7 and MDA-MB-231 human breast cancer cells and MCF-10A untransformed breast epithelial cells.
This in vitro study was conducted on methanolic extracts of cleavers to evaluate activity on human breast cancer cells and healthy breast epithelial cells. G. aparine was tested at various concentrations and time points (up to 72 hours) and the cytotoxicity, cell cycle effects, and cell death pathways were evaluated. The results showed that the extract induced apoptosis in MDA-MB-231 cells (human breast cancer, triple negative), necrosis in MCF-7 cells (human breast cancer, oestrogen receptor positive), and G1 cell cycle arrest after 72 hours of treatment. Results showed that the extract was cytotoxic against the cancer cells, apparently sparing normal healthy cells.
In previous studies, methanol and ethyl acetate extracts of G. aparine were also reported to be effective against human breast cancer cells and human colon cancer cells.
These findings support the therapeutic potential of cleavers as an adjunct to cancer care; however, more research is required to evaluate whether these results translate into humans.
Evidence strength: All anticancer evidence is in vitro (cell culture). No animal or human clinical studies have been published. These findings are preliminary and should not be interpreted as clinical evidence of efficacy.
5.6 Diuretic and Renal Effects
Cleavers has a gentle soothing diuretic action that has been used in herbal traditions to increase the flow of urine. Due to these properties, cleavers has been considered appropriate for use where there is irritation and inflammation in the bladder, urethra, or vas deferens.
A 2025 phytochemical study specifically examined cleavers as a candidate for renoprotective applications, with the study taking place in response to the worldwide renal disease burden as an effort to determine the bioactive fingerprint of G. aparine and to link its ethnobotanical history with modern pharmacological knowledge. The high concentrations of flavonoids, phenols, and tannins confirmed substantial antioxidant capacity, which is crucially relevant to oxidative stress implicated in the pathogenesis and progression of chronic kidney disease (CKD).
Little formal research has been conducted on cleavers in clinical settings, though preliminary lab experiments suggest it may have antispasmodic activity.
Evidence strength: Traditional use as a diuretic is long-standing and cross-cultural. However, there are no published randomized clinical trials evaluating cleavers as a diuretic in humans. Evidence for renoprotective effects is limited to in vitro phytochemical characterization.
5.7 Lymphatic System Support
Cleavers has many attributed actions on the body in herbal traditions, including being lymphatic, diuretic, alterative, cooling, anti-inflammatory, and vulnerary. Modern research on cleavers remains limited, especially human clinical research, but phytochemical studies indicate that Galium aparine contains phenolic compounds, flavonoids, iridoids, and other constituents with antioxidant and immunomodulatory activity in laboratory studies.
Evidence strength: Lymphatic tonic effects are supported only by long-standing traditional use and by indirect laboratory evidence. No clinical trials specifically evaluating lymphatic outcomes have been published.
5.8 Skin and Topical Applications
In the ethnopharmacology of many countries, the herb of G. aparine is used for the treatment of skin diseases. Topically, cleavers has been used for inflammation of the skin, minor injuries, and conditions such as eczema and psoriasis.
Poultices and washes made from cleavers were traditionally used to treat a variety of skin ailments, light wounds, and burns, and as a pulp it was applied to relieve venomous bites and stings.
Evidence strength: Topical use for skin conditions rests on traditional evidence and the in vitro wound-healing study described above. No controlled clinical trials in humans have evaluated topical cleavers for any specific skin condition.
6. Body Systems Associated with Cleavers
- Lymphatic system: Historically used as a lymphatic tonic and cleanser; attributed to increase lymphatic drainage and break up lymphatic congestion, especially in the pelvis.
- Urinary tract: Galium is also considered demulcent for the urinary tract, giving it indications for cystitis, urethritis, prostatitis, and pyelonephritis.
- Skin and integumentary system: Can be used topically for inflammation of the skin, minor injuries, and conditions such as eczema and psoriasis.
- Immune system: Laboratory evidence demonstrates that G. aparine extract exhibits immunomodulatory properties, and gene expression changes observed in animal studies support its potential as a natural agent for immune augmentation.
- Gastrointestinal system: Iridoid glycosides including asperuloside are mildly laxative and purgative.
- Renal system: Having a proven history in use as a kidney and lymphatic tonic, G. aparine is considered a promising candidate for examination of its modern uses in treating or preventing kidney diseases as well as ensuring proper distribution of fluids in the body.
7. Dosage Forms and Reported Dosages
Cleavers tincture and tea are most widely recommended by herbal practitioners. Tincture (½–1 teaspoon or 3–5 ml) can be taken three times per day. Tea is made by steeping 2–3 teaspoons (10–15 grams) of the herb in 1 cup (250 ml) of hot water for ten to fifteen minutes, and people can drink three or more cups per day.
The following dosage figures are those reported in herbal medicine references and are presented as documented values, not as recommendations:
- Infusion: 1–2 teaspoons per cup, steeped for 10 minutes, 1–2 cups three times daily.
- Fluid extract (1:1, 25% ethanol): 2–4 ml three times daily.
- Tincture (1:5, 25% ethanol): 4–10 ml three times daily.
- Fresh juice (succus): 3–15 ml three times daily. Poultice and skin wash are applied as needed.
Despite the compelling ethnobotanical history and confirmatory pharmacological studies, there remains a critical need for detailed, standardized phytochemical profiling. Variation in soil, climate, and harvesting techniques can significantly alter the concentration of active constituents, leading to inconsistencies in therapeutic outcomes.
8. Safety Considerations and Interactions
G. aparine is generally regarded as safe; side effects are generally not seen in practice when used at recommended doses, according to naturopathic herbal reference sources. At the time of writing of the PeaceHealth Health Information Library entry, there were no well-known side effects caused by this supplement.
When used appropriately, cleavers is generally considered safe for most people, but potential side effects include skin irritation, gastrointestinal discomfort, or allergic reactions, particularly in individuals with sensitive skin or existing allergies.
Diuretic Interaction Potential
Cleavers may interact with certain pharmaceuticals, particularly those affecting the kidneys or urinary system. It is known to increase urine production and may enhance the effects of diuretic medications. This can lead to dehydration or electrolyte imbalances if not monitored.
Contact Dermatitis
Some people may experience a rash when they touch this plant. The hooked hairs that densely cover the stems and leaves are the physical basis for this potential irritation, particularly in sensitive individuals.
Contraindications
Cleavers has been noted as contraindicated in diabetes due to its diuretic action. Those experiencing edemas due to impaired heart or kidney function are also cautioned about taking diuretics in many medical texts. During pregnancy, cleavers is not recommended due to limited safety data and potential risks.
Herb–Drug Interactions
At the time of publication, the PeaceHealth Health Information Library noted no well-known supplement or food interactions with this supplement. Cleavers may potentially interact with supplements that have similar diuretic or renal effects. For seriously ill patients, such as those undergoing cancer treatment, it is advised to work with a medical herbalist alongside doctors and oncologists to ensure all healthcare providers are aware of potential herb–drug interactions.
Evidence Gaps in Safety
Modern research on cleavers remains limited, especially human clinical research. These constituents give support for why many herbalists have valued cleavers, even though modern clinical studies are lacking. Despite the compelling ethnobotanical history and confirmatory pharmacological studies, there remains a critical need for detailed, standardized phytochemical profiling. The absence of clinical trial data means that the full safety profile in humans — including dose-response relationships, long-term tolerability, and drug interaction potential — has not been formally characterized.
References
- Ilina T, et al. Phytochemical Profiles and In Vitro Immunomodulatory Activity of Ethanolic Extracts from Galium aparine L. Plants (Basel). 2019;8(12):541. PMC6963662.
- Lee S, Park S, Park H. Immuno-Enhancing Effects of Galium aparine L. in Cyclophosphamide-Induced Immunosuppressed Animal Models. Nutrients. 2024;16(5):597. PMC10934713.
- Dowlati Beirami A, et al. Bringing back Galium aparine L. from forgotten corners of traditional wound treatment procedures: an antimicrobial, antioxidant, and in-vitro wound healing assay along with HPTLC fingerprinting study. BMC Complement Med Ther. 2024;24:279. PMC11267910.
- Çiçek SS, et al. Effects of Galium aparine extract on the cell viability, cell cycle and cell death in breast cancer cell lines. PubMed 27085941.
- A Review of Phytochemical and Pharmacological Studies on Galium verum L., Rubiaceae. PMC12029887. 2025.
- Galium aparine. Wikipedia.
- Talha M, Akram M, Rashid A. The Lymphatic Lineage: Unraveling the Phytochemical and Renoprotective Potential of Galium aparine (Cleavers). TPM. 2025;32(S7). ResearchGate.
- Talha M, Akram M, Rashid A. The Lymphatic Lineage: Unraveling the Phytochemical and Renoprotective Potential of Galium aparine (Cleavers). TPM – Testing, Psychometrics, Methodology in Applied Psychology. 2025;32(S7).
- Marciano M. Galium aparine. The Naturopathic Herbalist.
- Cleavers (Galium aparine): Benefits, Uses, Safety, Research. Herbal Reality.
- Cleavers — Health Information Library. PeaceHealth.
- Cleavers Plant (Galium aparine): Benefits, Identification & How to Use. The Old Farmer's Almanac.
- Review on phytochemical constituents and pharmacological activities of genus Galium. Journal of Applied Pharmaceutical Science.
- Galium aparine L. Plants of the World Online. Royal Botanic Gardens, Kew.
- Galium aparine L. Monograph. Belfast Herbalist (citing Grieve, Gerard, Culpeper, Dioscorides).
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