Alongside diet and lifestyle changes, goat’s rue has been seen to show significant benefits to blood glucose regulation including increasing insulin sensitivity. Consequently, it may be used as part of a treatment plan for the management of diabetes although insulin-dependant diabetic individuals, or those taking other diabetic drugs such as metformin, would be strongly advised to only do so under the guidance of both their healthcare provider and an experienced herbal practitioner. It can also be used, on its own or in combination with other herbs, to increase milk flow in breast-feeding mothers. Its diuretic action means it can be used to reduce fluid retention (1,2,3).

Goat’s rue is considered to be a drying and cooling herb. Its strength is in supporting the underlying processes of digestion, metabolism and elimination within the human body thus bringing excess or insufficiency into balance. As a diuretic, it helps to aid the elimination of toxins through the kidneys and reduce fluid retention.

Goat’s rue helps to increase the utilisation of glucose in fat and muscle cells, and reduces insulin resistance, thereby reducing blood sugar levels in the body. It helps to balance insulin levels, and supports both insulin-dependent and non-insulin-dependent diabetics to regulate blood glucose levels. It is known to reduce appetite and can aid in weight loss and in the management of metabolic syndrome. It is these mechanisms that led to the discovery of metformin (medication prescribed for diabetes), which is derived from the active ingredient, guanidine (1,2,3).

Culpeper (1616–1654) said that a bath made with goat’s rue was “very refreshing to wash the feet of people tired with over walking”.Parkinson (1567–1650) who is considered to be one of the great English herbalists and botanists as well as apothecary to King James I, recognised its potential antimicrobial action when he spoke of its benefits as “powerfull & effectuall against the plague or pestilence, or any infectious or pestilentious fevers or diseases, that breake forth into spots or markes, as the measells, purples & the small pocks…”. Its use in treating the plague is presumed to have been the reason behind its German name of pestilenzkraut translating directly as ‘pestilence herb’.

However, it is also recorded as having been indicated for conditions similar to those it is commonly used for today. Since mediaeval times it has been prescribed to manage the symptoms of diabetes such as frequent urination and intense thirst as well as being recognised to increase milk yield in nursing mothers (4).

Goat’s rue was denied approval by the German Commission E for its use in the treatment of diabetes, as a diuretic or galactagogue due to a considered lack of evidence regarding its effectiveness. In reality, it is safely and effectively used by many herbal practitioners today, frequently alongside other herbs whilst optimising diet and lifestyle.

Digestive system

Goats rue is used by practitioners to support both pancreatic function and the digestive system of patients with diabetes or those who are considered pre-diabetic. Its ability to lower blood glucose levels is attributed to a number of actions including decreasing the absorption of glucose from the gut, regulating its metabolism by the liver, increasing its utilisation in fat and muscle cells and decreasing insulin resistance so cells are able to metabolise glucose more efficiently. This allows for better blood glucose regulation, optimising the chance of this remaining within acceptable levels and may allow insulin-dependent diabetic patients to, under close medical supervision, reduce their insulin dosage. Whilst in the diabetic patient long-term high blood glucose levels (hyperglycaemia) are associated with permanent damage to various parts of the body particularly the small blood vessels, nerves, kidneys and eyes it is also deemed to be detrimental in many other conditions including cardiovascular health, where they can increase the risk of heart attack or stroke.

It is also valued for its beneficial effects on the pancreas, protecting the cells that produce insulin and may be useful when insufficient digestive enzymes result in digestive issues such as indigestion or constipation (1,2,3).

Immune system

Goat’s rue aids the immune system both as an antibacterial and diaphoretic herb. It is effective against certain types of bacteria including Staphylococcus aureus, commonly implicated in infections of the skin. In cases of illness that involve excess fever, the diaphoretic action of this herb promotes sweating to cool the body and reduce a temperature. Along with other herbs including fennel, fenugreek and milk-thistle, goat’s rue may be useful in promoting lactation in breast-feeding mothers who are experiencing insufficient milk production. However, other factors including maternal perception of not producing enough milk, nutritional and hydration status and social situation should not be overlooked as they may significantly impact milk production and need addressing as an integral part of any treatment plan. Goat’s rue may be used as a diuretic reducing fluid retention within the body by promoting elimination through the kidneys (1,2,3).

Research has shown goat’s rue to have pronounced antidiabetic effects within the laboratory based in-vivo environment. Administration of a preparation derived from the leaves and stems of the plant was demonstrated to reduce levels of fasting blood glucose and improve insulin sensitivity. Furthermore, it is suggested that it has a protective effect on the insulin producing β cells of the pancreas (5). These effects have been commonly attributed to the guanidine alkaloid constituents. However, studies of the phenolic compounds and microelements found within goat’s rue suggest that these may also contribute to its beneficial effects in the management of blood glucose levels. Research specifically focused on the flavonoid content of the plant confirmed its ability to improve glycosidic metabolism. Microelements found to be present in goat’s rue including copper, manganese and selenium were also all found to demonstrate significant benefits in the management of diabetes (6).

Laboratory studies into potential anti-obesity effects of goat’s rue reported weight loss, reduced blood glucose levels and decreased food consumption in pair-feeding studies using mice. Although the initial weight loss is attributable to a reduced food intake, it was discovered that changes in weight were independent of this and in time exceeded that of the control subjects (7).

A study was carried out into the antibacterial properties of goat’s rue against both gram positive and gram negative bacteria with the aim of investigating the claim that it increased post-surgical healing time of the skin. Although cold water extraction of the herb showed no antibacterial action, the 60% aqueous ethanolic solution significantly inhibited a number of bacteria including Staphylococcus aureus, a common pathogen implicated in infections of the skin and surgical wounds (8).

The origins of the Latin name for goat’s rue, Galega officinalis,  is said to have come from the Greek ‘gala’, meaning milk, and ‘ago’ meaning to lead, hence ‘to lead to milk’ referring to the plant’s usefulness as a fodder to increase milk flow in lactating domestic herds of cows, sheep or goats.

It is native to Europe, Russia and Iran but has been introduced to many other regions. Although it has been widely cultivated in gardens for its attractive appearance, it may be found growing wild in moist ground such as around ponds and alongside streams (14).

There are no concerns currently regarding the sustainability of goat’s rue and the population is listed as stable in the UK. As a nitrogen fixing plant it has been cultivated as a green manure crop providing essential nutrients when ploughed back into the soil (15).

Habitat loss and over-harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must, therefore, ensure that we source our medicines with sustainability in mind.

The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.

The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world is now certificated through the emergence of credible international voluntary sustainability standards (VSS). 

Read our article on Herbal quality and safety: What to know before you buy and Sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.

Herbal medicines are often very safe to take; however, their safety and efficacy can be jeopardised by quality issues. So, it is important to buy herbal medicines from a reputable supplier, from sources known to test their herbs to ensure there is no contamination, adulteration or substitution with incorrect plant matter, as well as ensuring that recognised marker compounds are at appropriate levels in the herbs.

Some important quality assurances to look for are certified organic labelling, the correct scientific/botanical name, and the availability of information from the supplier about ingredient origins. A supplier should be able to tell you where the herbs have come from, what contaminants are not in the herb, and what the primary compounds are.

Goat’s rue is not difficult to grow from seed and once established will readily self seed. It prefers moist soil in full sun to partial shade. It can be sown directly into the soil outside in spring or seedlings can be transplanted. As it becomes quite a large plant of up to a metre tall with multiple branches, seedlings should be planted approximately a metre apart (16).

1. Busti A. The Mechanism of Goat’s Rue or French Lilac in the Treatment of Diabetes Mellitus. www.ebmconsult.com. Published 2015. Accessed September 7, 2020. https://www.ebmconsult.com/articles/goats-rue-french-lilac-diabetes
2. Mcintyre A. Complete Herbal Tutor : The Definitive Guide to the Principles and Practices of Herbal Medicine (Second Edition). Aeon Books Limited; 2019.
3. Thomsen M. Phytotherapy Desk Reference. 6th ed. Aeon Books; 2022.
4. Hadden D. Goat’s rue – French lilac – Italian fitch – Spanish sainfoin: gallega officinalis and metformin:The Edinburgh connection. Royal College of Physicians of Edinburgh. 2005;35(258-260). https://www.rcpe.ac.uk/journal/issue/journal_35_3/hadden_goats%20rue.pdf
5. Hachkova H, Nagalievska M, Soliljak Z, et al. Medicinal Plants Galega officinalis L. and Yacon Leaves as Potential Sources of Antidiabetic Drugs. Antioxidants. 2021;10(9):1362. doi:https://doi.org/10.3390/antiox10091362
6. Barchuk O, Denys A, Lysiuk R, Zaliska O, Smalyuh O, Nester M. Experimental study of goat’s rue (Galega Officinalis L.) herb and its liquid extracts. The Pharma Innovation Journal . 2017;6(11):393-397. https://www.thepharmajournal.com/archives/2017/vol6issue11/PartF/6-11-26-299.pdf
7. Mooney MH, Fogarty S, Stevenson C, et al. Mechanisms underlying the metabolic actions of galegine that contribute to weight loss in mice. British Journal of Pharmacology. 2008;153(8):1669-1677. doi:https://doi.org/10.1038/bjp.2008.37
8. Pundarikakshudu K, Patel JK, Bodar MS, Deans SG. Anti-bacterial activity of Galega officinalis L. (Goat’s Rue). Journal of Ethnopharmacology. 2001;77(1):111-112. doi:https://doi.org/10.1016/s0378-8741(01)00250-1
9. Keeler RF, Johnson AE, Stuart LD, Evans JO. Toxicosis from and possible adaptation to Galega officinalis in sheep and the relationship to Verbesina encelioides toxicosis. Veterinary and human toxicology. 1986;28(4):309-315. https://pubmed.ncbi.nlm.nih.gov/3750812/
10. Natural Medicines. Goat’s rue. naturalmedicines.therapeuticresearch.com. Published 2024. https://naturalmedicines.therapeuticresearch.com/databases/food
11. Fisher C. Materia Medica of Western Herbs. Aeon Books; 2018.
12. Bednarska K, Kuś P, Fecka I. Investigation of the Phytochemical Composition, Antioxidant Activity, and Methylglyoxal Trapping Effect of Galega officinalis L. Herb In Vitro. Molecules. 2020;25(24):5810. doi:https://doi.org/10.3390/molecules25245810
13. Native Plant Trust. Galega officinalis (professor-weed): Go Botany. gobotany.nativeplanttrust.org. Published 2024. https://gobotany.nativeplanttrust.org/species/galega/officinalis/
14. Royal Botanical Gardens Kew. Galega officinalis L. | Plants of the World Online | Kew Science. Plants of the World Online. Published 2015. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:495681-1
15. Chadburn H. IUCN Red List of Threatened Species: Galega officinalis. IUCN Red List of Threatened Species. Published February 5, 2014. Accessed November 13, 2022. https://www.iucnredlist.org/species/203352/2764313
16. Jekka’s Herbs. Galega officinalis. Jekka’s. Published 2023. Accessed November 10, 2024. https://www.jekkas.com/products/goats-rue