TempoLife › Features › Herb and spice reference: evidence, dose and interactions › liquorice
Liquorice
Liquorice — what the European monograph actually supports, what it is not for, the form and how long it is meant to be used, side effects, and the 2 medicine interactions documented for it.
This is a reference page, not a diagnosis and not a prescription. Herbal products are real pharmacology: they have effects, side effects and interactions with medicines. Tell your doctor and your pharmacist everything you take, including teas and supplements, and never stop or change a prescribed medicine because of anything you read here.
What it is
Glycyrrhiza glabra L. — root (Liquiritiae radix)
Local names across the region this site serves: lagrits (ET) · lakritsi (FI) · солодка (RU).
Grouped here under Digestion, bloating and the bowel. Regulatory position: EU herbal monograph — traditional use; also a regulated food ingredient.
What the evidence supports
The registered indication: Digestive complaints including burning sensation and dyspepsia; and as an expectorant in cough associated with a cold.
Liquorice is where the Nordic sweet counter and the medicine cabinet meet, and it has one of the best-understood toxicities in the whole herbal field. Glycyrrhizin — glycyrrhizinic acid — inhibits an enzyme in the kidney that normally protects the mineralocorticoid receptor from cortisol. Blocked, cortisol acts like aldosterone: sodium and water are retained, potassium is lost, and blood pressure rises. In real life that shows up as swollen ankles, headache, muscle weakness or cramps, and in severe cases dangerously low potassium with heart-rhythm disturbance. It is genuinely dose-dependent and it arrives as often through sweets and salty liquorice as through any medicine. The European Commission's Scientific Committee on Food concluded that a regular intake above 100 mg of glycyrrhizinic acid a day could produce these effects in some adults, and that remains the reference point used across Europe. Sensitivity varies widely, and people with high blood pressure, heart failure, kidney disease or low potassium are affected at lower intakes. EU food labelling rules require confectionery and drinks above a set glycyrrhizinic-acid level to state that they contain liquorice, and higher still to warn that people with high blood pressure should avoid excessive consumption — those words on a bag of sweets are a regulatory safety warning, not decoration.
C — Traditional use only Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it.
What it is not for
Stomach ulcers, reflux managed on medication, or as a daily habit by anyone with raised blood pressure. Deglycyrrhizinated liquorice products exist precisely because the active constituent is the problematic one.
Form, strength and how long
Dried root as tea, extracts, lozenges and cough preparations; deglycyrrhizinated extracts; and the whole confectionery aisle, where salty liquorice can carry substantial amounts.
Duration. Medicinal liquorice preparations should not be used for longer than four to six weeks without medical advice — the limit exists because the effect on potassium and blood pressure accumulates.
No gram figure appears on this page on purpose. The plant part, the extraction solvent and the drug-to-extract ratio together define a preparation, and a number taken from one does not describe another. The reasoning is set out on the hub; the amount that applies to you is the one printed on the pack you are holding, and a pharmacist will read it with you.
Side effects
Raised blood pressure, fluid retention and ankle swelling, low potassium with muscle weakness and cramps, headache. Severe cases present with heart-rhythm disturbance and have required hospital treatment.
Who should avoid it
Avoid in pregnancy in more than incidental amounts: Finnish cohort research has linked heavy liquorice consumption during pregnancy with poorer outcomes in the children, and Finnish authorities advise pregnant women to avoid large amounts. Avoid with hypertension, heart failure, kidney disease, low potassium and liver disease.
Interactions with medicines
| Medicine or substance | What is described |
|---|---|
| Blood-pressure medicines, diuretics and corticosteroids | Liquorice pushes blood pressure up and works directly against blood-pressure medicines. Diuretics and corticosteroids lower potassium too, so combining them with liquorice compounds the loss. |
| Digoxin | Low potassium makes the heart more sensitive to digoxin. This is a recognised route to digoxin toxicity and it starts with something bought as a sweet. |
The reverse view — start from the medicine rather than the plant — is in the medicine, food and alcohol interactions reference, and summarised for every herb on this site.
Sources: European Medicines Agency — Committee on Herbal Medicinal Products (HMPC), European Union herbal monographs · European Commission Scientific Committee on Food — opinion on glycyrrhizinic acid · checked 2026-09-06
Frequently asked questions
What is liquorice used for?
Digestive complaints including burning sensation and dyspepsia; and as an expectorant in cough associated with a cold. Liquorice is where the Nordic sweet counter and the medicine cabinet meet, and it has one of the best-understood toxicities in the whole herbal field. Glycyrrhizin — glycyrrhizinic acid — inhibits an enzyme in the kidney that normally protects the mineralocorticoid receptor from cortisol. Blocked, cortisol acts like aldosterone: sodium and water are retained, potassium is lost, and blood pressure rises. In real life that shows up as swollen ankles, headache, muscle weakness or cramps, and in severe cases dangerously low potassium with heart-rhythm disturbance. It is genuinely dose-dependent and it arrives as often through sweets and salty liquorice as through any medicine. The European Commission's Scientific Committee on Food concluded that a regular intake above 100 mg of glycyrrhizinic acid a day could produce these effects in some adults, and that remains the reference point used across Europe. Sensitivity varies widely, and people with high blood pressure, heart failure, kidney disease or low potassium are affected at lower intakes. EU food labelling rules require confectionery and drinks above a set glycyrrhizinic-acid level to state that they contain liquorice, and higher still to warn that people with high blood pressure should avoid excessive consumption — those words on a bag of sweets are a regulatory safety warning, not decoration.
Does liquorice work?
Graded C here: Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it. Stomach ulcers, reflux managed on medication, or as a daily habit by anyone with raised blood pressure. Deglycyrrhizinated liquorice products exist precisely because the active constituent is the problematic one.
How much liquorice should I take?
This reference does not print gram figures, because they do not transfer between preparations of different extract strength. What can be said honestly is the form and the duration: Dried root as tea, extracts, lozenges and cough preparations; deglycyrrhizinated extracts; and the whole confectionery aisle, where salty liquorice can carry substantial amounts. Medicinal liquorice preparations should not be used for longer than four to six weeks without medical advice — the limit exists because the effect on potassium and blood pressure accumulates.
What are the side effects of liquorice?
Raised blood pressure, fluid retention and ankle swelling, low potassium with muscle weakness and cramps, headache. Severe cases present with heart-rhythm disturbance and have required hospital treatment.
Does liquorice interact with medicines?
Yes — documented for Blood pressure, Digoxin. Each one is described on this page, with a link to the medicine-side reference where one exists.
Others in digestion, bloating and the bowel
Peppermint
Symptomatic relief of minor spasms of the gastrointestinal tract, flatulence and abdominal pain, especially in irritable bowel syndrome, for gastro-resistant oil capsules; the leaf is registered for mild digestive complaints.
Caraway
Mild spasmodic gastrointestinal complaints including bloating and flatulence.
Ginger
Prevention of nausea and vomiting in motion sickness, and mild digestive complaints such as bloating.
Fennel
Mild spasmodic gastrointestinal complaints including bloating and flatulence; and as an expectorant in cough associated with a cold.
Turmeric
Relief of digestive disturbances such as a feeling of fullness and flatulence.
Milk thistle
Relief of digestive complaints, including a feeling of fullness and indigestion.
Keep the whole list in one place
TempoLife logs supplements alongside food, sleep and how you actually felt — so the answer to "what are you taking?" is a screen, not a guess.