Couchgrass

The dried rhizome, sometimes called “twitch root”, is taken as a decoction, a 1:1 liquid extract or a tincture ^{2,22Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 22British Herbal Medicine Association · 1983British Herbal Pharmacopoeia}.

Western herbalists class couchgrass as a demulcent diuretic, used for inflamed and irritated states of the urinary tract. The British Herbal Pharmacopoeia lists it for cystitis, urethritis and prostatitis, for benign prostatic hyperplasia, and for kidney stones and gravel, with cystitis with irritation or inflammation as its specific indication ^{2,22Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 22British Herbal Medicine Association · 1983British Herbal Pharmacopoeia}.

The same pharmacopoeia pairs it with buchu for cystitis and with hydrangea for prostatic enlargement ^{22Reference 22British Herbal Medicine Association · 1983British Herbal Pharmacopoeia}.

It is also given for gout and rheumatic complaints, and for irritable coughs and inflamed digestion.

Couchgrass rhizome has long been used in European folk medicine ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}. In Greece it was taken for cystitis, kidney stones and prostate enlargement, for gallstones, for arthritis and rheumatism, and to lower raised cholesterol ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}. In Bulgaria and Italy it was used mainly as a diuretic, and also as a laxative ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}.

The rhizome has also been eaten. Dried and ground, it makes a flour that has served as a famine food, and roasted it has been used as a coffee substitute ^{23Reference 23Plants For A FutureElytrigia repens (Couch Grass) — PFAF Plant DatabaseView study →}.

A decoction of the rhizome is used in Morocco as a traditional treatment for diabetes ^{2,8Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 8Eddouks et al. · 2005AnimalHypoglycaemic effect of Triticum repens PView study →}.

Two placebo-controlled trials of Renalof, a product combining couchgrass extract with mannitol and magnesium, have been completed. One was a single-blind Phase 2 study of stones under 10 mm, with 120 patients taking 650 mg twice daily and 35 taking placebo; the other was a double-blind study of upper urinary tract stone volume in 82 patients ^{17,18Reference 17Efficacy et al.RCTClinicalTrials.gov NCT04695951View study →Reference 18Agropyron repens et al.RCTClinicalTrials.gov NCT04860492View study →}. Neither has posted results. A third trial, of a four-herb product (birch, Herniaria, Viburnum and couchgrass), is recruiting 120 patients ^{19Reference 19Neorenal Forte as adjuvant for eliminatiRCTClinicalTrials.gov NCT06651294View study →}.

In an unblinded study of 50 children aged 5–14 with kidney stones, 25 took a couchgrass extract at 5 mg/kg for 60 days. Stone number fell in 88% of treated children and 12% of controls; the study had no placebo, and its inclusion criteria and control treatment were not described ^{2,16Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 16Moohy Alosy et al. · 2019RCTRole of Agropyron repens extract in treatment of renal calculus in the pediatric group — randomised studyView study →}.

A further unblinded study gave 50 adults potassium citrate with 100 mg of couchgrass extract, and reported greater reductions in stone number and size than potassium citrate alone. There was no couchgrass-only group, so the herb’s own effect could not be judged ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}.

In rats, a four-herb mixture including couchgrass reduced calcium-oxalate crystal deposits ^{7Reference 7Crescenti et al. · 2015AnimalAntiurolithiasic effect of a plant mixture (Herniaria glabra, Agropyron repens, Equisetum arvense, Sambucus nigra) in experimentally induced nephrolithiasis in rats — animal modelView study →}. The couchgrass infusion alone did not improve the main calcium-oxalate risk factors ^{6Reference 6Grases et al. · 1995AnimalEffect of Herniaria hirsuta and Agropyron repens on calcium oxalate urolithiasis risk in rats — animal modelView study →}.

Gap: no placebo-controlled result for couchgrass alone.

Increasing urine flow to flush the urinary tract in minor urinary complaints is the indication in the EU traditional-use monograph ^{27Reference 27European Medicines Agency · 2022ReviewEuropean Union herbal monograph on Agropyron repens (L.) PView study →}.

In rats, a cold-water macerate at 50 mL/kg raised urine output to 1.42 times that of controls, and an injected hydroalcoholic extract to 1.62 times ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}. An infusion at 3 g per litre showed no diuretic effect, and the EU assessors found no animal data confirming a diuretic effect of the tea ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}.

The effect is attributed to the osmotic action of the rhizome’s sugar alcohols, mannitol (2–3%) and inositol, released with the fructan triticin ^{1,2,3Reference 1Zhakipbekov et al. · 2026Systematic reviewElymus repens (L.) Gould phytochemistry, pharmacological activities and therapeutic potential — systematic reviewView study →Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 3Bortolami et al. · 2022Metabolic profile of Agropyron repens rhizome herbal tea by HPLC-PDA-ESI-MS/MS analysisView study →}.

Gap: no human trial has measured urine output.

An acetone extract of the rhizome, at concentrations above 250 µg/mL, significantly reduced the attachment of uropathogenic E. coli to human T24 bladder cells, without harming either the bacteria or the cells ^{4Reference 4Beydokhti et al. · 2017In vitroHexadecyl coumaric acid ester from the rhizomes of Agropyron repens with antiadhesive activity against uropathogenic E. coli — in vitroView study →}. More water-soluble extracts had no effect ^{4Reference 4Beydokhti et al. · 2017In vitroHexadecyl coumaric acid ester from the rhizomes of Agropyron repens with antiadhesive activity against uropathogenic E. coli — in vitroView study →}. The active compound was (E)-hexadecyl-3-(4-hydroxyphenyl)-acrylate, a hexadecyl ester of coumaric acid, which also reduced bacterial invasion of the cells ^{4Reference 4Beydokhti et al. · 2017In vitroHexadecyl coumaric acid ester from the rhizomes of Agropyron repens with antiadhesive activity against uropathogenic E. coli — in vitroView study →}.

An earlier study found that a 50% ethanol extract reduced adhesion by acting on the bacteria’s outer membrane proteins (IC₂₅ 630 µg/mL) ^{5Reference 5Rafsanjany et al. · 2013In vitroAntiadhesion as a functional concept for protection against uropathogenic E. coli: in vitro studies with traditionally used plantsView study →}. A four-herb German aqueous formula (birch, couchgrass, goldenrod and restharrow) showed anti-adhesive activity that came mainly from the birch and goldenrod ^{1Reference 1Zhakipbekov et al. · 2026Systematic reviewElymus repens (L.) Gould phytochemistry, pharmacological activities and therapeutic potential — systematic reviewView study →}.

In an uncontrolled post-marketing study, 313 patients with urinary tract infection or irritable bladder took 50–60 drops of a fluid extract for 12 days. By the end, 32–53% were free of symptoms, depending on the diagnosis, and no side effects were reported ^{2,15Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 15Hautmann et al. · 2000ObservationalFluid extract of Agropyron repens for urinary tract infections or irritable bladder: multicentric post-marketing surveillance — observational}. An earlier open study in 99 patients reported similar improvement ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}.

Gap: the active ester is lipophilic and present in small amounts, and it is not known whether it reaches the urine ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}. No controlled trial has tested couchgrass for urinary infection.

A freeze-dried decoction of the rhizome, given to rats at 20 mg/kg, lowered blood glucose in normal and diabetic rats. In diabetic rats glucose returned to normal after two weeks of daily dosing, with no change in insulin levels ^{8Reference 8Eddouks et al. · 2005AnimalHypoglycaemic effect of Triticum repens PView study →}. The same extract lowered plasma triglycerides and cholesterol in rats ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}.

In vitro, hydroalcoholic extracts inhibited the carbohydrate-digesting enzymes α-amylase and α-glucosidase ^{9,10Reference 9Deveci et al. · 2020In vitroAntioxidant, cytotoxic, and enzyme inhibitory activities of Agropyron repens and Crataegus monogyna — in vitroView study →Reference 10NEAGU et al. · 2019In vitroAntioxidant and antidiabetic properties of polyphenolic-rich extracts of Apium graveolens and Agropyrum repens — in vitroView study →}. The activity is attributed to the phenolic acids and flavonoids, including quercetin and tricin.

Gap: no human data.

Couchgrass extracts scavenge free radicals in standard assays (DPPH, reducing power), and the activity tracks the phenolic and flavonoid content — chiefly caffeic acid, its caffeoyl- and feruloylquinic esters, and flavonoids such as tricin, luteolin and rutin ^{9,11Reference 9Deveci et al. · 2020In vitroAntioxidant, cytotoxic, and enzyme inhibitory activities of Agropyron repens and Crataegus monogyna — in vitroView study →Reference 11Petrova et al. · 2009Chemical composition of couch grass and antioxidant activity in allergic contact dermatitisView study →}.

Analysis of the rhizome tea confirms that these phenolics carry into the water ^{3Reference 3Bortolami et al. · 2022Metabolic profile of Agropyron repens rhizome herbal tea by HPLC-PDA-ESI-MS/MS analysisView study →}.

The assays used hydroalcoholic extracts, which are richer in phenolics than a tea, and all of the work is in vitro.

In a screen of Italian medicinal plants, an 80% ethanol extract of the rhizome given to rats at 100 mg/kg inhibited carrageenan paw swelling by 14%, against 45% for indometacin ^{2,12Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 12Mascolo et al. · 1987AnimalBiological screening of Italian medicinal plants for anti-inflammatory activity — animal modelView study →}.

A cream containing couchgrass extract sped recovery from allergic contact dermatitis in rats by four to five days, though it was less effective than a steroid cream ^{2,11Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →Reference 11Petrova et al. · 2009Chemical composition of couch grass and antioxidant activity in allergic contact dermatitisView study →}.

The candidate compounds are hydroxycinnamic-acid derivatives and flavones such as tricin ^{1Reference 1Zhakipbekov et al. · 2026Systematic reviewElymus repens (L.) Gould phytochemistry, pharmacological activities and therapeutic potential — systematic reviewView study →}.

Couchgrass has a long history in Western herbal medicine for gout and rheumatic complaints ^{1Reference 1Zhakipbekov et al. · 2026Systematic reviewElymus repens (L.) Gould phytochemistry, pharmacological activities and therapeutic potential — systematic reviewView study →}.

The reasoning is that the sugar alcohols increase urine flow and, with it, uric-acid excretion. No study has measured serum urate, uric-acid excretion or gout outcomes with couchgrass in animals or people.

Gap: there is no direct evidence on urate.

Record in use. The EU monograph lists no known side effects, no reported overdose and no reported interactions ^{27Reference 27European Medicines Agency · 2022ReviewEuropean Union herbal monograph on Agropyron repens (L.) PView study →}. About 400 patients in two uncontrolled studies of a fluid extract reported no adverse effects ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}.

Fluid intake. Adequate fluid is needed during use, so couchgrass is not recommended for people whose doctor has advised them to reduce fluid intake ^{27Reference 27European Medicines Agency · 2022ReviewEuropean Union herbal monograph on Agropyron repens (L.) PView study →}.

Children. The tea is not recommended under 12, and extracts and tinctures under 18, because of a lack of data ^{27Reference 27European Medicines Agency · 2022ReviewEuropean Union herbal monograph on Agropyron repens (L.) PView study →}.

Warning signs. Fever, painful urination, spasms or blood in the urine call for a doctor ^{27Reference 27European Medicines Agency · 2022ReviewEuropean Union herbal monograph on Agropyron repens (L.) PView study →}.

Diuretics. Prolonged use may lead to potassium loss ^{23Reference 23Plants For A FutureElytrigia repens (Couch Grass) — PFAF Plant DatabaseView study →}, so take care alongside potassium-depleting (loop and thiazide) diuretics.

Toxicity testing. The fluid extract was not mutagenic in the Ames test ^{2Reference 2European Medicines Agency · 2022Assessment report on Agropyron repens (L.) PView study →}. Reproductive, genotoxicity and carcinogenicity testing has not been done ^{27Reference 27European Medicines Agency · 2022ReviewEuropean Union herbal monograph on Agropyron repens (L.) PView study →}.

Grass allergy. As a grass, couchgrass is a possible allergen for people sensitised to grass pollen. The EU monograph lists hypersensitivity to the herb as its one contraindication ^{27Reference 27European Medicines Agency · 2022ReviewEuropean Union herbal monograph on Agropyron repens (L.) PView study →}.