Licorice: blood pressure, digestion and interactions — what precautions matter?

Licorice, from Glycyrrhiza roots, is not risk-free when taken in concentrated or regular forms. Glycyrrhizin, also called glycyrrhizic acid, can affect sodium-potassium balance and lead to higher blood pressure, low potassium and cardiovascular complications.

Glycyrrhizin is a major constituent of many licorice preparations. It can have mineralocorticoid-like effects: sodium and water retention, potassium loss and higher blood pressure. Not every sweet or flavour labelled licorice contains the same exposure; some products use other flavourings and actual content varies. [1][2][3]

The biological mechanism is better established than therapeutic benefits. A plausible mechanism does not turn an extract into a treatment.

Repeated exposure may contribute to hypertension, low potassium, oedema, muscle weakness and rhythm disturbances. Severe effects are uncommon but can be serious. Concern is greater with hypertension, cardiovascular or kidney disease, high salt intake or medicines that affect potassium. [2][3][4]

Do not use licorice to treat high blood pressure or low potassium. Marked weakness, palpitations, unusual cramps, swelling or feeling unwell need prompt medical advice.

Licorice root has traditional use in some digestive preparations, including for burning sensations or dyspepsia. This does not show that every extract relieves reflux, ulcers or digestive disease. Evidence on non-Chinese herbal medicines for functional dyspepsia remains insufficient. [1][5][6]

Persistent pain, repeated vomiting, blood in stools, unexplained weight loss or swallowing difficulty need medical assessment rather than self-medication with a plant.

Duration depends on the preparation and intended use. Infusion, root, tincture, dry extract and deglycyrrhizinated product are not interchangeable. European monographs frame preparations and durations; they do not validate continuous use of any product. [1]

Prolonged or repeated use of glycyrrhizin-containing licorice is particularly unsuitable without professional advice. Natural does not mean suitable every day for months.

The evidence is not sufficient to consider concentrated extracts safe during pregnancy or breastfeeding. As a precaution, seek medical advice and avoid self-medication. Extra care is also needed for children and people with cardiovascular, kidney, liver or autoimmune disease. [2][3]

Anyone on a low-salt diet, with abnormal potassium or taking several medicines should not add medicinal licorice without checking first.

The main concerns involve medicines affecting potassium or blood pressure: some diuretics, antihypertensives, corticosteroids and digoxin. NCCIH also reports interactions with corticosteroids; the exact list depends on product and dose. [3][4]

Before regular use, give a pharmacist or doctor the botanical name, form, stated glycyrrhizin content and complete medication list. Never stop or alter a medicine in order to take licorice.

• Check species and plant part.
• Distinguish flavouring, root, infusion, extract and deglycyrrhizinated products.
• Look for glycyrrhizin content or a glycyrrhizin-free statement when relevant.
• Check amount per serving and advised number of days.
• Be sceptical of claims about blood pressure, reflux, liver, energy or hormones.

Licorice may have a traditional place in selected digestive preparations, but glycyrrhizin requires particular caution. Blood pressure, potassium, heart, kidneys, pregnancy, breastfeeding, duration and interactions must be considered together. For persistent symptoms or regular medicines, professional assessment comes before self-medication.