Liquorice

Liquorice has a long history of use in both traditional and modern herbal medicine.  It is used for: 

Digestive support 

Liquorice has been traditionally used to help soothe the digestive tract.  It works to reduce inflammation and protect mucous membranes, offering relief from indigestion, heartburn and mild stomach discomfort.  Research shows that Liquorice stimulates mucus production in the digestive tract, which can help protect the gut lining.  Liquorice has been clinically shown to inhibit Helicobacter pylori, the primary cause of stomach ulcers, and helps eliminate the bacteria when combined with conventional treatments. 

Respiratory comfort 

Liquorice supports the respiratory system through its demulcent (soothing), anti-inflammatory, antitussive (cough-suppressing) and expectorant properties.  It helps calm irritated mucous membranes in the throat and lungs, reduces inflammation in the airways and loosens mucus so it is easier to clear from the respiratory tract.  Traditionally, it was used to ease coughs, sore throats, chest irritation and mild congestion. 

Adrenal function 

Liquorice supports adrenal function by helping to prolong the activity of cortisol, a key hormone involved in the stress response and energy regulation.  It slows the breakdown of cortisol in the body, which can support stamina, blood sugar balance and resilience during periods of physical or emotional stress.  For this reason, Liquorice has traditionally been used to help with fatigue and exhaustion. 

Anti-inflammatory and antioxidant effects 

Liquorice reduces inflammation by modulating inflammatory pathways and calming overactive immune responses.  These actions soothe irritated tissues throughout the body, including the gut, respiratory tract and skin, and help ease discomfort associated with acute or chronic inflammation.  

Skin conditions  

Liquorice supports skin health through its anti-inflammatory, soothing and antioxidant properties, which calm irritation, redness and itching.  It is commonly used for skin conditions including eczema, psoriasis and dermatitis, as it can reduce inflammatory responses and support skin barrier repair.  Its anti-microbial properties support skin healing and protect against infection. 

Oral health 

Liquorice supports oral health through its antimicrobial, anti-inflammatory and demulcent (soothing) properties.  It can help inhibit the growth of bacteria associated with dental plaque, cavities and gum disease, while calming inflamed or irritated gums.  Traditionally, it has been used to heal mouth ulcers, sore throats and gum discomfort. 

The root and underground rhizomes of the Liquorice plant contain the highest concentration of active constituents. These include glycyrrhizin, flavonoids, coumarins and polysaccharides. As the root accumulates the highest level of actives, this is the part used in herbal teas, fluid extracts and supplements.

Triterpenoid saponins (glycyrrhizin) 

• Glycyrrhizin, which is 50 times sweeter than sugar, gives Liquorice its distinct sweetness. 
• Glycyrrhizin displays anti-inflammatory, antioxidant, anti-viral and anti-arthritic activity, and is responsible for Liquorices ability to heal gastric ulcers. 

Flavonoids (liquiritin and glabrene) 

• Flavonoids reduce inflammation by mitigating oxidative stress and inhibiting pro-inflammatory cytokines, associated with conditions such as gastritis, hepatitis and arthritis. 
• Flavonoids support gut health by reinforcing the integrity of the gut lining, helping to protect against stomach ulcers.  

Polysaccharides (mucilage, lignans and starch) 

• Enhance immunity by increasing the production of T and B lymphocytes and promoting phagocytosis (the destruction of foreign organisms). 
• Mucilage creates a gel-like consistency that soothes and protects irritated and inflamed tissues. Internally, this has a demulcent action on mucous membranes. Externally, this has an emollient effect on the skin. 

Coumarins (glycycoumarin, liqcoumarin, glabrocoumarone, herniarin, umbelliferone and glycyrin) 

• Glycycoumarin functions as an antispasmodic, working to relax smooth muscles. 
• Coumarins exert significant anti-inflammatory and antioxidant effects, protecting against cell injury and degradation. 

Liquorice is safe to consume in food amounts for most people.  However, regular and excessive intake of Liquorice confectionery has been associated with elevated blood pressure.  High doses of glycyrrhizin, an active constituent of liquorice, may cause sodium depletion, leading to water retention, swelling and increased blood pressure.  For this reason, it is not recommended to exceed 100 mg per day of glycyrrhizin. 

Deglycyrrhizinated Liquorice (DGL) is a preparation in which glycyrrhizin has been removed and is typically used to inhibit ulcer formation and protect the stomach lining from damage. 

Typical adult dosages: 

• Infusion using dried root: 3-12 g/day 
• Fluid extract 1:1 between 1.5-4 mL/day 

Always follow dosage recommendations and consult with a Naturopath or Medical Herbalist if using other medications or herbal products.  

Liquorice is generally not recommended during pregnancy or breastfeeding. High and frequent Liquorice consumption as confectionary has been linked to increased risk of high blood pressure and preterm delivery.

Consumption of Liquorice fluid extract during pregnancy and breastfeeding should be guided by a Naturopath or Medical Herbalist, for safe dosing and monitoring.

Liquorice exerts a mineralocorticoid effect, meaning it mimics hormones that cause the body to retain sodium and water while losing potassium.  This can lead to: 

• Elevated blood pressure 
• Low potassium levels (hypokalaemia) 

Both of which can worsen hypertension and place strain on the cardiovascular system.  For this reason, people with existing high blood pressure, heart disease, or kidney disease should be particularly cautious with Liquorice consumption. 

Liquorice can interact with various medications, often through effects on electrolyte balance or hormonal pathways. 

Common interactions include: 

• Antihypertensives (blood pressure medications): Liquorice may reduce their effectiveness. 
• Diuretics: Particularly potassium-lowering types, as Liquorice can worsen potassium loss.  
• Cardiac glycosides: Liquorice-induced hypokalaemia can enhance digoxin toxicity. 
• Corticosteroids: Liquorice may potentiate corticosteroid effects and electrolyte disturbances.  
• Other drugs affected by electrolyte balance: Such as some antiarrhythmics or laxatives. 

Always tell your healthcare provider about Liquorice use when you are on medications, especially for heart, blood pressure or kidney-related conditions. 

The Netherlands is currently the world leader in Liquorice consumption. On average, Dutch people consume around 2 kgs of Liquorice per person each year, more than any other country. While Scandinavia, Spain, Germany, and Italy are also notable producers and consumers, the Dutch culture of Liquorice, known locally as ‘drop’, stands out on a global scale.

Historically, Liquorice was sold in pharmacies as a herbal remedy for coughs and colds.  An influenza outbreak in 1890 had a significant impact in the Netherlands, solidifying Liquorice’s popularity and shifting its role from medicine to sweet treat. 

The Dutch affinity for Liquorice, particularly salty Liquorice, stems from a blend of tradition, culture and taste preference.  

• Liquorice sweets have been a staple of Dutch confectionery for generations. 
• Salty Liquorice, flavoured with ammonium chloride (salmiak), is especially popular and represents a taste that is unfamiliar to many outside northern Europe. 

Growing liquorice can be rewarding but requires patience, as the valuable root takes 3-4 years to develop. 

Climate & soil 

Liquorice prefers: 

• Full sun 
• Deep, well-drained soil 
• A slightly sandy, moisture-retentive but not waterlogged environment  

It can grow to about 1 metre tall with fern-like foliage and may produce delicate violet-blue flowers.  

Planting 

• You can grow from seed or from established root divisions.  
• Soaking seeds overnight can improve germination.  
• Ensure seedlings or young plants are kept moist and protected while establishing. 

Tip: Liquorice roots are deep and extensive, plan your garden space accordingly. 

In New Zealand’s temperate climate, the best time to plant liquorice is in late spring or early summer, once the risk of frost has passed and the soil has warmed.  

This gives the plant the longest possible growing season to develop its deep roots before cooler weather arrives. 

Patience is key.  Liquorice roots need time to build up their sweetness and beneficial compounds. 

Harvest timing 

• Liquorice roots are typically harvested in autumn, after 3–4 years of growth, once the growing season is complete and the roots have matured.  
• Some growers harvest part of the root while leaving the main runners before replanting so that it can continue growing. 

Harvest roots carefully with a spade or fork, clean them, and dry them for use in teas or extracts. 

Dang, L., Jin, Y., Yuan, Y., Shao, R., & Wang, Y. (2024). Licorice: A comprehensive review of its chemical composition, pharmacodynamics and medicinal value. Acupuncture and Herbal Medicine. https://doi.org/10.1097/hm9.0000000000000103  

Leite, C. dos S., Bonafé, G. A., Carvalho Santos, J., Martinez, C. A. R., Ortega, M. M., & Ribeiro, M. L. (2022). The anti-inflammatory properties of Licorice (Glycyrrhiza glabra)-derived compounds in intestinal disorders. International Journal of Molecular Sciences, 23(8), 4121. https://doi.org/10.3390/ijms23084121  

Mamedov, N. A., & Egamberdieva, D. (2019). Phytochemical constituents and pharmacological effects of licorice: A review. Plant and Human Health, Volume 3, 3, 1–21. https://doi.org/10.1007/978-3-030-04408-4_1  

Rahnama, M., Davood Mehrabani, Japoni, S., Majid Edjtehadi, & Mehdi Saberi Firoozi. (2013). The healing effect of licorice (Glycyrrhiza glabra) on Helicobacter pylori infected peptic ulcers. Journal of Research in Medical Sciences: The Official Journal of Isfahan University of Medical Sciences, 18(6), 532. https://pmc.ncbi.nlm.nih.gov/articles/PMC3818629/  

Sharma, V., Katiyar, A., & Agrawal, R. C. (2018). Glycyrrhiza glabra: Chemistry and pharmacological activity. Reference Series in Phytochemistry, 87–100. https://doi.org/10.1007/978-3-319-27027-2_21  

Zhang, J., Xu, X., Li, N., Cao, L., Sun, Y., Wang, J., He, S., Si, J., & Qing, D. (2022). Licoflavone B, an isoprene flavonoid derived from licorice residue, relieves dextran sodium sulfate-induced ulcerative colitis by rebuilding the gut barrier and regulating intestinal microflora. European Journal of Pharmacology, 916, 174730. https://doi.org/10.1016/j.ejphar.2021.174730