Food and medicine interaction

Black licorice and licorice root (glycyrrhizin) and digoxin (Lanoxin)

TheoreticalEvidence level: theoretical. Suggested by how the food and the drug work, or by lab data. Not shown in people.

Last reviewed October 18, 2026

What can happen

Licorice can lower blood potassium, and low potassium makes digoxin toxicity more likely. The combination could raise the risk of dangerous heart rhythm problems.

Why it happens: Glycyrrhizin causes potassium loss through the kidneys; hypokalemia is a recognized risk factor for digoxin toxicity.
At ordinary food amounts: Regular eating is the concern. The potassium drop in trials came from chronic intake of at least 100 mg of glycyrrhizic acid a day; an occasional piece is less likely to matter, but the margin with digoxin is narrow.

What to do

If you take digoxin, avoid regular licorice candy or licorice root unless your prescriber says otherwise, and ask about any herbal product first. Do not change your digoxin on your own.

Never stop or change a prescribed medicine without talking to the prescriber.

Common questions

Can I have black licorice and licorice root (glycyrrhizin) while taking heart rhythm medicines?

If you take digoxin, avoid regular licorice candy or licorice root unless your prescriber says otherwise, and ask about any herbal product first. Do not change your digoxin on your own. Regular eating is the concern. The potassium drop in trials came from chronic intake of at least 100 mg of glycyrrhizic acid a day; an occasional piece is less likely to matter, but the margin with digoxin is narrow.