Liquorice extract is derived from the plant Glycyrrhiza glabra. Liquorice extract is used as a sweetener and as a flavouring agent in some lollies and herbal tea and is also marketed as a dietary supplement.
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Can liquorice be bad for you?
Key points about liquorice
- Liquorice extract is used as a sweetener and flavouring agent in some lollies and herbal teas. It's also marketed as a dietary supplement.
- Eating small amounts now and again is safe for most people, but it may be harmful in large amounts or in combination with some medicines.
- Liquorice can cause low blood potassium, abnormal heart rhythms, muscle cramps and weakness, high blood pressure and water retention.
- Side effects are more likely if you have heart failure or high blood pressure, including high blood pressure during pregnancy.
- If you've been consuming liquorice and have heart palpitations, muscle weakness or other health-related problems, stop eating it and seek medical advice
Liquorice extract, especially when consumed in large quantities, can cause side effects. Glycyrrhizin in liquorice can cause the potassium levels in your body to fall. When that happens, you may experience abnormal heart rhythms, as well as high blood pressure, water retention and swelling (oedema), extreme tiredness and heart failure.
You are most at risk of side effects from liquorice and should avoid it if you have:
- high blood pressure, including high blood pressure during pregnancy
- heart failure.
In general, a maximum of 100 mg/day glycyrrhizin is recommended, which is about 60–70 g of liquorice sweets1.
Liquorice can interact with some medicines used to treat high blood pressure or heart failure, such as diuretics (also called water pills), digoxin and fludrocortisone. It can also interact with some herbs and dietary supplements. Get advice from your GP or pharmacist if you have questions about possible interactions with a medicine or supplement you're taking.
- Liquorice – all sorts of side effects and interactions(external link) Medsafe Prescriber Update, NZ, 2019
- Licorice root(external link) National Institutes of Health, US, 2016
- Can eating too much black liquorice be bad for you?(external link) NHS, UK, 2018
Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.
Reviewed by: Angela Lambie, Pharmacist, Auckland
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