Goat's Rue

What Is Goat’s Rue?

Goat’s rue is a European and west Asian legume used in herbal medicine to support milk supply and to lower blood sugar. Its guanidine alkaloid galegine was the chemical starting point for the biguanide drugs, which led to metformin ^{2,8Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →Reference 8Hadden · 2005ReviewGoat’s rue — French lilac — Italian fitch — Spanish sainfoin: Galega officinalis and metformin: the Edinburgh connection — historical reviewView study →}.

Galega officinalis is an upright perennial that grows to about 1.5 m, with pinnate leaves and spikes of white to purple pea flowers ^{20Reference 20AliAli, S. I. (family ed.). Galega officinalis Linn. — species description and distribution. Flora of Pakistan, Papilionaceae. eFloras. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220005407View study →}. It is thought to have originated around the eastern Mediterranean and the Black Sea, and it has a long history of ornamental and medicinal use in Europe ^{23Reference 23Bromfield et al. · 2019Invasive Galega officinalis (goat’s rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World — field / molecularView study →}.

Galegine content varies with plant part and growth stage, and is highest in the reproductive parts, the flowers and developing pods ^{19Reference 19Oldham et al. · 2011Galegine content in goatsrue (Galega officinalis) varies by plant part and phenological growth stage — analytical / toxicologyView study →}. Research has looked mostly at blood sugar and body weight in animals and cells ^{1,2Reference 1Palit et al. · 1999AnimalNovel weight-reducing activity of Galega officinalis in mice — animal modelView study →Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →}. The human trials concern milk supply, and all of them used goat’s rue in a combination product with silymarin ^{10,13Reference 10Zecca et al. · 2016RCTEfficacy of a galactogogue containing silymarin-phosphatidylserine and galega in mothers of preterm infants: a randomised controlled trial — RCTView study →Reference 13Cragg et al. · 2026Systematic reviewHerbal galactagogues to improve breastmilk production and lactation in mothers of preterm babies: a systematic review of clinical trials — systematic reviewView study →}.

Goat’s rue is also called French lilac, Italian fitch and Spanish sainfoin ^{8Reference 8Hadden · 2005ReviewGoat’s rue — French lilac — Italian fitch — Spanish sainfoin: Galega officinalis and metformin: the Edinburgh connection — historical reviewView study →}. It is a close relative of fodder galega (Galega orientalis), a forage plant that is not treated as a noxious weed ^{23Reference 23Bromfield et al. · 2019Invasive Galega officinalis (goat’s rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World — field / molecularView study →}.

How Is Goat’s Rue Used?

• Aerial parts — the dried flowering tops, the part used in folk medicine for diabetes and for milk supply ^{14Reference 14Rasekh et al. · 2008AnimalAcute and subchronic oral toxicity of Galega officinalis in rats — animal modelView study →}.
• Liquid extract — a 1:2 extract of the dried herb, taken at 15–30 mL a week in Western herbal practice.
• Combination products — goat’s rue with silymarin and phosphatidylserine, sold to support milk supply after birth ^{10Reference 10Zecca et al. · 2016RCTEfficacy of a galactogogue containing silymarin-phosphatidylserine and galega in mothers of preterm infants: a randomised controlled trial — RCTView study →}.

Traditional Uses

European Folk Medicine

Goat’s rue is used in European folk medicine to increase milk supply and to treat diabetes ^{4,14Reference 4Bednarska et al. · 2020In vitroInvestigation of the phytochemical composition, antioxidant activity, and methylglyoxal trapping effect of Galega officinalis L. herb — in vitroView study →Reference 14Rasekh et al. · 2008AnimalAcute and subchronic oral toxicity of Galega officinalis in rats — animal modelView study →}. It was also part of a plant mixture used for diabetes ^{1Reference 1Palit et al. · 1999AnimalNovel weight-reducing activity of Galega officinalis in mice — animal modelView study →}.

It carries a traditional reputation as a diuretic and as an emmenagogue.

Its use for diabetes led chemists to galegine, and from galegine to the biguanide drugs and metformin ^{2,8Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →Reference 8Hadden · 2005ReviewGoat’s rue — French lilac — Italian fitch — Spanish sainfoin: Galega officinalis and metformin: the Edinburgh connection — historical reviewView study →}.

Botany

Goat’s rue is an erect perennial herb in the pea family (Fabaceae), growing up to 150 cm tall ^{20Reference 20AliAli, S. I. (family ed.). Galega officinalis Linn. — species description and distribution. Flora of Pakistan, Papilionaceae. eFloras. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220005407View study →}. Its branches are smooth or thinly hairy ^{20Reference 20AliAli, S. I. (family ed.). Galega officinalis Linn. — species description and distribution. Flora of Pakistan, Papilionaceae. eFloras. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220005407View study →}.

Its leaves are pinnate, with 9–21 elliptic to lanceolate leaflets 1.5–5 cm long and arrow-shaped stipules at the base ^{20Reference 20AliAli, S. I. (family ed.). Galega officinalis Linn. — species description and distribution. Flora of Pakistan, Papilionaceae. eFloras. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220005407View study →}. Its flowers grow in racemes 7–10 cm long, each carrying 25–50 white to purple pea flowers ^{20Reference 20AliAli, S. I. (family ed.). Galega officinalis Linn. — species description and distribution. Flora of Pakistan, Papilionaceae. eFloras. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220005407View study →}. The pods are narrow, about 2–3 mm wide, and hold 2–10 seeds ^{20Reference 20AliAli, S. I. (family ed.). Galega officinalis Linn. — species description and distribution. Flora of Pakistan, Papilionaceae. eFloras. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220005407View study →}.

Goat’s rue needs a specific root-nodule bacterium, Neorhizobium galegae, to fix nitrogen and grow normally ^{23Reference 23Bromfield et al. · 2019Invasive Galega officinalis (goat’s rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World — field / molecularView study →}.

The plant is poisonous to sheep. In feeding trials, doses as small as 0.8 g of dried plant per kg of body weight a day caused breathing difficulty in ewes ^{22Reference 22Keeler et al. · 1986Toxicosis from and possible adaptation to Galega officinalis in sheep and the relationship to Verbesina encelioides toxicosis — animal (sheep)View study →}. Fatal poisonings of sheep, with fluid filling the chest, have been recorded in France ^{24Reference 24Puyt et al. · 1981Case reportFatal poisoning of sheep by Galega officinalis (French honeysuckle) — veterinary case reportsView study →}.

Distribution

Goat’s rue is thought to have originated around the eastern Mediterranean and the Black Sea. People have spread it through Europe, western Asia and North Africa, and more recently to North and South America and New Zealand ^{23Reference 23Bromfield et al. · 2019Invasive Galega officinalis (goat’s rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World — field / molecularView study →}. The Flora of Pakistan records it in Pakistan, central and southern Russia, Lebanon, the Caucasus, and central and southern Europe ^{20Reference 20AliAli, S. I. (family ed.). Galega officinalis Linn. — species description and distribution. Flora of Pakistan, Papilionaceae. eFloras. http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220005407View study →}. It is spreading northwards in the UK ^{8Reference 8Hadden · 2005ReviewGoat’s rue — French lilac — Italian fitch — Spanish sainfoin: Galega officinalis and metformin: the Edinburgh connection — historical reviewView study →}.

It was introduced to North America in the late 19th century as an ornamental or a trial crop ^{23Reference 23Bromfield et al. · 2019Invasive Galega officinalis (goat’s rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World — field / molecularView study →}. It became abundant in northern Utah ^{22Reference 22Keeler et al. · 1986Toxicosis from and possible adaptation to Galega officinalis in sheep and the relationship to Verbesina encelioides toxicosis — animal (sheep)View study →}, and it has established on moist, disturbed ground in Ontario ^{23Reference 23Bromfield et al. · 2019Invasive Galega officinalis (goat’s rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World — field / molecularView study →}. It is regarded as a noxious weed in North America, both because it spreads and because it poisons livestock ^{23Reference 23Bromfield et al. · 2019Invasive Galega officinalis (goat’s rue) plants in Canada form a symbiotic association with strains of Neorhizobium galegae sv. officinalis originating from the Old World — field / molecularView study →}.

Where goat’s rue grows as an invasive weed, gathering it from the wild removes a problem plant rather than depleting a native one.

Growing Conditions

Cultivation snapshot for Goat's Rue

LifeperennialZoneUSDA 3–8

• Thrives in full sun on moist to wet, even waterlogged ground — streamsides, ditches and low pastures are its natural niche.
• A hardy clump-forming perennial, cold-tolerant through roughly USDA zones 3–8, dying back each winter and regrowing from the crown.
• As a legume it fixes its own nitrogen and asks little of soil fertility; it self-seeds freely and spreads readily once established.
• Regulated as a Federal Noxious Weed in the United States (and toxic to livestock) — do not plant it where prohibited, and check local rules first.

Grow it yourself

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How to growComing soon

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Indications

• Diabetes and high blood sugar [aerial parts; European folk use] ⚠Caution: No human trial has tested goat’s rue itself. The evidence comes from galegine and from extracts in animals and cells ^1,2,3,7.
• Low milk supply [aerial parts; European folk use, and combination products] ⚠Caution: The human trials used goat’s rue only with silymarin and phosphatidylserine, so its own contribution is unknown ^10,13.
• Excess weight [aerial parts] ⚠Caution: Weight loss has been shown only in mice, at 10% of the diet ¹.
• Fluid retention [aerial parts; traditional diuretic]

Pharmacology & Research

Most research on goat’s rue is on its alkaloid galegine, studied in rodents and cells for its effects on blood sugar and body weight ^{1,2,7Reference 1Palit et al. · 1999AnimalNovel weight-reducing activity of Galega officinalis in mice — animal modelView study →Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →Reference 7LaMoia et al. · 2022In vitroMetformin, phenformin, and galegine inhibit complex IV activity and reduce glycerol-derived gluconeogenesis — in vitro / in vivoView study →}. No randomised trial has tested goat’s rue for a metabolic outcome in people. The human trials concern milk supply, and all used a combination product with silymarin and phosphatidylserine ^{10,11,12,13Reference 10Zecca et al. · 2016RCTEfficacy of a galactogogue containing silymarin-phosphatidylserine and galega in mothers of preterm infants: a randomised controlled trial — RCTView study →Reference 11Serrao et al. · 2018RCTThe long-term efficacy of a galactagogue containing silymarin-phosphatidylserine and galega on milk production of mothers of preterm infants — RCT follow-upView study →Reference 12Castoldi et al. · 2014ObservationalSilymarin/galega administration in term and preterm mothers to sustain breast feeding: an observational study — observationalView study →Reference 13Cragg et al. · 2026Systematic reviewHerbal galactagogues to improve breastmilk production and lactation in mothers of preterm babies: a systematic review of clinical trials — systematic reviewView study →}.

Galegine content varies about sevenfold between plant parts, from about 1 mg/g in stems to 7 mg/g in reproductive tissue ^{19Reference 19Oldham et al. · 2011Galegine content in goatsrue (Galega officinalis) varies by plant part and phenological growth stage — analytical / toxicologyView study →}.

1. Antidiabetic

Galegine activates AMPK and stimulates glucose uptake in fat and muscle cells ^{2Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →}. Like metformin, it inhibits mitochondrial complex IV at clinically relevant concentrations, which suppresses glucose production from glycerol in the liver ^{7Reference 7LaMoia et al. · 2022In vitroMetformin, phenformin, and galegine inhibit complex IV activity and reduce glycerol-derived gluconeogenesis — in vitro / in vivoView study →}.

Guanidine, the parent compound of galegine, increased glucose uptake in cultured muscle cells through imidazoline I2 receptors and AMPK ^{6Reference 6Lui et al. · 2010In vitroActivation of imidazoline I2B receptors is linked with AMP kinase pathway to increase glucose uptake in cultured C2C12 cells — in vitroView study →}.

For the herb itself, a 90% acetone–water extract inhibited the carbohydrate-digesting enzymes sucrase (91%), maltase (63%), α-amylase (60%) and α-glucosidase (54%) in vitro ^{3Reference 3Sukhtezari et al. · 2024In vitroIn vitro antidiabetic and antioxidant activities of Galega officinalis extracts — in vitroView study →}. In mice, goat’s rue at 10% of the diet lowered serum glucose over 28 days ^{1Reference 1Palit et al. · 1999AnimalNovel weight-reducing activity of Galega officinalis in mice — animal modelView study →}.

Gap: no human trial has tested goat’s rue for blood sugar. The strongest data are for galegine as an isolated molecule, and for metformin.

2. Weight Reduction

Goat’s rue at 10% of the diet caused significant weight loss over 28 days in both normal and genetically obese (ob/ob) mice, and post-mortem examination found a striking absence of body fat ^{1Reference 1Palit et al. · 1999AnimalNovel weight-reducing activity of Galega officinalis in mice — animal modelView study →}. In normal mice the weight loss was largely independent of food intake; in obese mice it came with a persistent fall in food intake ^{1Reference 1Palit et al. · 1999AnimalNovel weight-reducing activity of Galega officinalis in mice — animal modelView study →}.

Galegine in the diet also reduced body weight in mice, and pair-feeding showed that part of the effect was independent of food intake. In cells, galegine activated AMPK, inhibited acetyl-CoA carboxylase, reduced lipolysis, and down-regulated fatty acid synthase and its regulator SREBP ^{2Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →}.

Analogues in which the guanidine group was replaced lost the weight-reducing effect ^{9Reference 9Coxon et al. · 2009AnimalBenzylguanidines and other galegine analogues inducing weight loss in mice — animal modelView study →}.

Gap: the work is in rodents and cells, and 10% of the diet is far above a herbal dose.

3. Antioxidant

A 90% acetone–water extract gave the strongest ABTS, hydroxyl-radical and FRAP activity. A 70% acetone extract was best in the DPPH test, and an ethanol–water extract in metal chelation ^{3Reference 3Sukhtezari et al. · 2024In vitroIn vitro antidiabetic and antioxidant activities of Galega officinalis extracts — in vitroView study →}.

A detailed chemical study found strong antiradical activity in the flavonols and hydroxycinnamic acids. Galegine, hydroxygalegine and the flavonoids also trapped methylglyoxal, a reactive compound linked to glycation ^{4Reference 4Bednarska et al. · 2020In vitroInvestigation of the phytochemical composition, antioxidant activity, and methylglyoxal trapping effect of Galega officinalis L. herb — in vitroView study →}.

In diabetic rats, an alkaloid-free fraction reduced oxidative stress in the liver ^{5Reference 5Hachkova et al. · 2026AnimalAmelioration of oxidative stress and hepatocellular mitochondrial dysfunction by bioactive compounds isolated from Galega officinalis in streptozotocin-induced diabetic rats — animal modelView study →}.

Gap: the evidence is mostly in vitro, with no human antioxidant measurement.

4. Galactagogue

In a double-blind RCT in 100 mothers of preterm infants, 5 g a day of a combination of silymarin–phosphatidylserine and galega, taken from day 3 to day 28 after birth, increased milk production at day 7 and day 30. Median daily production was 200 ml, against 115 ml on placebo, and no adverse reactions were seen ^{10Reference 10Zecca et al. · 2016RCTEfficacy of a galactogogue containing silymarin-phosphatidylserine and galega in mothers of preterm infants: a randomised controlled trial — RCTView study →}.

At three months, 22 mothers from the galactagogue group and 12 from the placebo group were feeding only breast milk. Six-month data were too sparse to evaluate ^{11Reference 11Serrao et al. · 2018RCTThe long-term efficacy of a galactagogue containing silymarin-phosphatidylserine and galega on milk production of mothers of preterm infants — RCT follow-upView study →}. An earlier observational study of 32 mothers also reported sustained milk production ^{12Reference 12Castoldi et al. · 2014ObservationalSilymarin/galega administration in term and preterm mothers to sustain breast feeding: an observational study — observationalView study →}.

A 2026 systematic review of herbal galactagogues for mothers of preterm babies found low-certainty evidence that the combination raises milk volume, by about 105 ml a day at day 7 ^{13Reference 13Cragg et al. · 2026Systematic reviewHerbal galactagogues to improve breastmilk production and lactation in mothers of preterm babies: a systematic review of clinical trials — systematic reviewView study →}.

Gap: no trial has tested goat’s rue alone, so its share of the effect cannot be separated from that of silymarin.

5. Hepatoprotective

In streptozotocin-diabetic rats (8 per group), an alkaloid-free fraction of goat’s rue given at 600 mg/kg a day for 14 days restored mitochondrial respiration in liver cells, including the activity of respiratory-chain complexes I–III, and reduced oxidative stress ^{5Reference 5Hachkova et al. · 2026AnimalAmelioration of oxidative stress and hepatocellular mitochondrial dysfunction by bioactive compounds isolated from Galega officinalis in streptozotocin-induced diabetic rats — animal modelView study →}.

Gap: one animal study, with no dose-ranging, no replication and no human data.

6. Antiplatelet

In two in-vitro reports from one research group, a purified 100–140 kDa polysaccharide–protein fraction of goat’s rue inhibited platelet aggregation triggered by ADP (50% inhibition at 11.2 µg/mL), collagen and thrombin. It also partly broke up platelets that had already clumped ^{15,16Reference 15Atanasov et al. · 2002In vitroAnti-platelet fraction from Galega officinalis L. inhibits platelet aggregation — in vitroView study →Reference 16Atanasov · 1999In vitroInhibiting effect of desalted extract from Galega officinalis L. on platelet aggregation — in vitroView study →}.

The activity has not been tested in animals or people. It is the basis of a caution about combining goat’s rue with anticoagulant or antiplatelet drugs.

Gap: the active fraction is a purified polysaccharide–protein complex, and whether a tincture or tea delivers it is unknown.

7. Antihypertensive

Galegine injected at 2.5–10 mg/kg produced an immediate, dose-dependent fall in mean arterial pressure of about 40%, with a rise in heart rate, in anaesthetised hypertensive rats ^{17Reference 17Wang et al. · 2021AnimalAntihypertensive effect of galegine from Biebersteinia heterostemon in rats — animal modelView study →}.

The galegine in this study was extracted from Biebersteinia heterostemon, a Tibetan medicinal plant, not from goat’s rue ^{17Reference 17Wang et al. · 2021AnimalAntihypertensive effect of galegine from Biebersteinia heterostemon in rats — animal modelView study →}.

Gap: no study has tested goat’s rue itself; the effect comes from galegine from a different plant, injected into anaesthetised animals.

8. Antipyretic

Galegine and a galegine-containing extract produced a progressive, dose-dependent fall in body temperature in mice with yeast-induced fever, supported by molecular-docking work ^{18Reference 18Nawaz et al. · 2025AnimalGalegine, a bioprivileged alkaloid from Tithonia tubaeformis: antipyretic activity insights — animal modelView study →}. The galegine was isolated from Tithonia tubaeformis, not from goat’s rue ^{18Reference 18Nawaz et al. · 2025AnimalGalegine, a bioprivileged alkaloid from Tithonia tubaeformis: antipyretic activity insights — animal modelView study →}.

Gap: a single study, with galegine from a different plant, no goat’s rue extract tested and no human data.

Mechanisms

Galegine is dimethylallylguanidine, the chemical ancestor of metformin ^{8,9Reference 8Hadden · 2005ReviewGoat’s rue — French lilac — Italian fitch — Spanish sainfoin: Galega officinalis and metformin: the Edinburgh connection — historical reviewView study →Reference 9Coxon et al. · 2009AnimalBenzylguanidines and other galegine analogues inducing weight loss in mice — animal modelView study →}. It has been studied for AMPK activation, for inhibition of acetyl-CoA carboxylase and fatty acid synthesis, and for inhibition of mitochondrial complex IV, which reduces glucose production in the liver ^{2,7Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →Reference 7LaMoia et al. · 2022In vitroMetformin, phenformin, and galegine inhibit complex IV activity and reduce glycerol-derived gluconeogenesis — in vitro / in vivoView study →}.

The flavonoids and hydroxycinnamic acids carry the antioxidant activity, and a polysaccharide–protein fraction the antiplatelet activity ^{3,4,15Reference 3Sukhtezari et al. · 2024In vitroIn vitro antidiabetic and antioxidant activities of Galega officinalis extracts — in vitroView study →Reference 4Bednarska et al. · 2020In vitroInvestigation of the phytochemical composition, antioxidant activity, and methylglyoxal trapping effect of Galega officinalis L. herb — in vitroView study →Reference 15Atanasov et al. · 2002In vitroAnti-platelet fraction from Galega officinalis L. inhibits platelet aggregation — in vitroView study →}.

Clinical Trials

No registered trial targets a glycemic, weight or lipid endpoint for goat’s rue. The only relevant registration is a silymarin–galega galactagogue combination (status unknown); other “Galega” results are metformin or goat-milk studies.

Last checked: February 2026.

Phytochemistry

Goat’s rue’s signature constituent is galegine, a guanidine alkaloid (dimethylallylguanidine) ^{9Reference 9Coxon et al. · 2009AnimalBenzylguanidines and other galegine analogues inducing weight loss in mice — animal modelView study →}. Water infusions of three batches of the dried herb contained on average 6.6 mg/g galegine and 1.7 mg/g 4-hydroxygalegine ^{4Reference 4Bednarska et al. · 2020In vitroInvestigation of the phytochemical composition, antioxidant activity, and methylglyoxal trapping effect of Galega officinalis L. herb — in vitroView study →}. An older analysis put galegine at about 0.46% of the plant ^{21Reference 21Keeler et al. · 1992Concentration of galegine in Verbesina encelioides and Galega officinalis and the toxic and pathologic effects induced by the plants — animal (sheep) / analyticalView study →}.

The polyphenol fraction is dominated by glycosylated flavonols, chiefly rutin at 1.7–3.3 mg/g, with other quercetin and kaempferol glycosides, and by monocaffeoylhexaric acids ^{4Reference 4Bednarska et al. · 2020In vitroInvestigation of the phytochemical composition, antioxidant activity, and methylglyoxal trapping effect of Galega officinalis L. herb — in vitroView study →}. The same study tentatively identified the quinazoline alkaloids vasicine (peganine) and vasicinol ^{4Reference 4Bednarska et al. · 2020In vitroInvestigation of the phytochemical composition, antioxidant activity, and methylglyoxal trapping effect of Galega officinalis L. herb — in vitroView study →}.

The glucoside galuteolin was first isolated from goat’s rue, in 1923 ^{25Reference 25Barger G · 1923Galuteolin, a new glucoside from Galega officinalis — isolation studyView study →}.

Galegine concentration varies with plant part and growth stage. In one study, reproductive tissue held about 7 mg/g, leaves 4 mg/g and stems 1 mg/g, and the whole-stalk concentration peaked at the immature-pod stage ^{19Reference 19Oldham et al. · 2011Galegine content in goatsrue (Galega officinalis) varies by plant part and phenological growth stage — analytical / toxicologyView study →}.

Galegine also occurs in other plants. Verbesina encelioides contains about 0.08% ^{21Reference 21Keeler et al. · 1992Concentration of galegine in Verbesina encelioides and Galega officinalis and the toxic and pathologic effects induced by the plants — animal (sheep) / analyticalView study →}, and the galegine used in the blood-pressure and fever studies came from Biebersteinia heterostemon and Tithonia tubaeformis ^{17,18Reference 17Wang et al. · 2021AnimalAntihypertensive effect of galegine from Biebersteinia heterostemon in rats — animal modelView study →Reference 18Nawaz et al. · 2025AnimalGalegine, a bioprivileged alkaloid from Tithonia tubaeformis: antipyretic activity insights — animal modelView study →}.

Studies of galegine from other plants, or of isolated galegine and metformin, should be read separately from studies of goat’s rue itself ^{17,18Reference 17Wang et al. · 2021AnimalAntihypertensive effect of galegine from Biebersteinia heterostemon in rats — animal modelView study →Reference 18Nawaz et al. · 2025AnimalGalegine, a bioprivileged alkaloid from Tithonia tubaeformis: antipyretic activity insights — animal modelView study →}.

Constituent Summary

Amounts are mg per gram of dried herb unless noted.

Dosage

No dosing study of goat’s rue exists. The research doses below come mostly from animal and isolated-galegine work.

Traditional Dosage

Safety & Pregnancy

Goat’s rue lowers blood sugar, and the amount of galegine in it varies with plant part and growth stage. The main cautions are low blood sugar alongside diabetes medicines, a possible bleeding interaction, and pregnancy.

Full Safety & Interactions Detail

Blood sugar. Galegine is glucose-lowering, so goat’s rue may add to the effect of insulin and other diabetes drugs, including sulfonylureas and metformin, and may cause low blood sugar ^{2,7Reference 2Mooney et al. · 2008In vitroMechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitroView study →Reference 7LaMoia et al. · 2022In vitroMetformin, phenformin, and galegine inhibit complex IV activity and reduce glycerol-derived gluconeogenesis — in vitro / in vivoView study →}. This is the most important interaction. It is pharmacodynamic; no CYP450 interaction has been shown.

Bleeding. A polysaccharide–protein fraction of the herb inhibits platelet aggregation in vitro ^{15,16Reference 15Atanasov et al. · 2002In vitroAnti-platelet fraction from Galega officinalis L. inhibits platelet aggregation — in vitroView study →Reference 16Atanasov · 1999In vitroInhibiting effect of desalted extract from Galega officinalis L. on platelet aggregation — in vitroView study →}. That gives a possible additive bleeding risk with anticoagulant or antiplatelet medicines and around surgery, though it has not been confirmed in people.

Plant part and growth stage. Galegine content is highest in reproductive tissue and peaks at the immature-pod stage ^{19Reference 19Oldham et al. · 2011Galegine content in goatsrue (Galega officinalis) varies by plant part and phenological growth stage — analytical / toxicologyView study →}. A preparation made from flowering or seeding tops can therefore be stronger than one made from leaves and stems.

Livestock poisoning. Goat’s rue poisons sheep, causing breathing difficulty, fluid in the chest and lung congestion; clinical signs appeared at 0.8 g of dried plant per kg a day in ewes, and fatal cases are recorded ^{22,24Reference 22Keeler et al. · 1986Toxicosis from and possible adaptation to Galega officinalis in sheep and the relationship to Verbesina encelioides toxicosis — animal (sheep)View study →Reference 24Puyt et al. · 1981Case reportFatal poisoning of sheep by Galega officinalis (French honeysuckle) — veterinary case reportsView study →}.

Animal toxicity studies. In rats, the oral LD50 of the aerial parts was above 5 g/kg ^{14Reference 14Rasekh et al. · 2008AnimalAcute and subchronic oral toxicity of Galega officinalis in rats — animal modelView study →}. Feeding 0.15–3% of the diet for 90 days raised serum cholesterol, CPK, LDH and bilirubin, lowered calcium, albumin, hematocrit, white cells and platelets, and caused sinusoidal congestion in the liver and bleeding in the lungs. The authors named the liver and lungs as target organs ^{14Reference 14Rasekh et al. · 2008AnimalAcute and subchronic oral toxicity of Galega officinalis in rats — animal modelView study →}.

Human data. No dedicated human safety or interaction study exists. The one human trial reported no adverse reactions to the silymarin–galega combination ^{10Reference 10Zecca et al. · 2016RCTEfficacy of a galactogogue containing silymarin-phosphatidylserine and galega in mothers of preterm infants: a randomised controlled trial — RCTView study →}.

References

1. Palit, P., Furman, B. L., & Gray, A. I. (1999). Novel weight-reducing activity of Galega officinalis in mice — animal model. Journal of Pharmacy and Pharmacology. https://pubmed.ncbi.nlm.nih.gov/10632090/
2. Mooney, M. H., Fogarty, S., Stevenson, C., et al. (2008). Mechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice — animal model / in vitro. British Journal of Pharmacology. https://pubmed.ncbi.nlm.nih.gov/18297106/
3. Sukhtezari, S., Sahari, M. A., Barzegar, M., & Azizi, M. H. (2024). In vitro antidiabetic and antioxidant activities of Galega officinalis extracts — in vitro. Food Science & Nutrition. https://pubmed.ncbi.nlm.nih.gov/39479699/
4. Bednarska, K., Kuś, P., & Fecka, I. (2020). Investigation of the phytochemical composition, antioxidant activity, and methylglyoxal trapping effect of Galega officinalis L. herb — in vitro. Molecules. https://pubmed.ncbi.nlm.nih.gov/33317096/
5. Hachkova, H., et al. (2026). Amelioration of oxidative stress and hepatocellular mitochondrial dysfunction by bioactive compounds isolated from Galega officinalis in streptozotocin-induced diabetic rats — animal model. Biomedicine & Pharmacotherapy. https://pubmed.ncbi.nlm.nih.gov/42105688/
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