Real licorice gets its sweetness from glycyrrhizin (glycyrrhizic acid), a compound in the root of the licorice plant that is many times sweeter than sugar. Glycyrrhizin is also why licorice has health warnings: in the body it is converted to glycyrrhetinic acid, which blocks an enzyme (11β-hydroxysteroid dehydrogenase type 2) that normally protects the kidneys from the effects of cortisol. The result, with high and sustained intake, resembles an excess of the hormone aldosterone: the body retains sodium and water and loses potassium.

What can happen

Effects reported in the medical literature after heavy, regular consumption include raised blood pressure, low potassium (hypokalaemia), muscle weakness, swelling and, in serious cases, heart-rhythm problems. These effects usually reverse when the person stops eating licorice. A dose-response study published in the Journal of Human Hypertension (Sigurjónsdóttir et al., 2001) found that blood pressure rose measurably even at moderate daily intakes over a few weeks.

The US Food and Drug Administration has advised that, for people aged 40 and over, eating 2 ounces (about 57 g) of black licorice a day for at least two weeks could lead to an irregular heart rhythm.

How much is a lot?

The EU's former Scientific Committee on Food concluded in 2003 that a regular intake of 100 mg of glycyrrhizic acid a day should not be exceeded. How much candy that equals depends entirely on the product: glycyrrhizin content varies widely between types and brands, and some licorice-flavoured sweets contain little or none. Packaging does not usually state the exact amount, so the EU label is the main guide.

The EU labelling rules

Under EU Regulation 1169/2011 (Annex III), confectionery and drinks containing glycyrrhizinic acid must carry warnings:

  • From 100 mg/kg in confectionery: the words "contains liquorice" (Dutch: "bevat zoethout").
  • From 4 g/kg in confectionery: additionally, "contains liquorice – people suffering from hypertension should avoid excessive consumption".

Similar thresholds apply to drinks. So if a Dutch drop bag carries the longer warning, it is a strong licorice product.

Who should be careful

  • People with high blood pressure, heart disease or kidney disease.
  • People taking medicines that lower potassium (such as some diuretics) or heart medicines such as digoxin; ask a doctor or pharmacist.
  • Pregnant women: several national food authorities advise limiting licorice during pregnancy.
  • Anyone eating large amounts every day, which is uncommon but does occur with habitual drop eaters.

Salmiak and sugar

The salty taste of zoute drop comes from ammonium chloride (E 510), an authorised food additive; its health questions are separate from glycyrrhizin and are discussed in salmiak. Like any sweet, drop also contains sugar or other sweeteners, so the usual dental and dietary advice applies. Sugar-free drop typically uses polyols, which can have a laxative effect in larger amounts.

If you have symptoms or a medical condition, talk to a doctor; this page summarises public guidance only.