Licorice and Levonorgestrel: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Levonorgestrel
Licorice
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased risk of fluid retention and elevated blood pressure
Interaction Deep Dive
Elevated blood pressure and fluid retention has been associated with concomitant use of licorice and oral contraceptives in case reports12, which may be related to estrogen and/or progesterone. The glycyrrhetinic acid component of licorice is metabolized to 3-monoglucuronyl-glycyrrhetinic acid (3MGA), which inhibits 11-beta-hydroxysteroid dehydrogenase and reduces cortisol breakdown, resulting in a hypermineralocorticoid effect 34.
Why it happens (mechanism)
Increased mineralocorticoid effect
Literature reports
3 reports — tap to read
a) A 21-year-old female developed headache and hypertension (190/120 mmHg), associated with licorice consumption (100 grams daily) along with an oral contraceptive. She was advised to discontinue eating licorice. Blood pressure remained elevated with treatment combining atenolol, lisinopril, hydrochlorothiazide, and amlodipine. Drug treatment was discontinued, and 2 weeks later blood pressure was 180/110 mmHg, potassium 2.6 mmol/L (normal, 3.8 to 5 mmol/L), bicarbonate 35.9 mmol/L (normal, 23 to 29 mmol/L). Plasma aldosterone was 160 picomoles/liter (pmol/L) (normal, 320 to 2000 pmol/L). The patient then admitted to replacing her licorice intake with two packets of Stimerolol Sugar Free(R) chewing gum per day. This chewing gum contains 585 mg licorice in each 15-gram packet, which equals 8% to 12% glycyrrhizinic acid. Her glycyrrhizinic acid intake was calculated to be 120 mg daily. Within 3 weeks of discontinuing the gum, her blood pressure and potassium level normalized 1.
b) A 35-year-old woman taking an oral contraceptive and chlorothiazide experienced hypokalemia (2.2 mmol/L). Her blood pressure was 140/80 mmHg. Chlorothiazide was stopped and potassium chloride 600 mg three times daily was started. After one week, potassium remained abnormal at 2 mmol/L; after 2 weeks, it decreased further to 1.5 mmol/L. Intravenous potassium supplementation was started. Although she denied licorice use, it was discovered that she used BenBits Cool Mint(R) chewing gum (Leaf, United Kingdom), 3 packets daily. This product contained 160 mg licorice in each 16-gram packet, of which 10% was glycyrrhizinic acid. After 2 days of intravenous potassium and 15 days of oral potassium, and within 3 weeks of discontinuing the chewing gum, edema disappeared, blood pressure decreased to 110/80 mmHg and potassium increased to 4.2 mmol/L. The authors attributed the hypokalemia to the licorice intake 1.
c) In a study of 4 groups of 6 healthy volunteers administered varying doses of licorice root, the group administered 814 mg of glycyrrhizin experienced a decrease in serum potassium from 4.25 millimoles/liter (mmol/L) to 3.53 mmol/L (p=0.014) after one week. Two of the subjects were taking oral contraceptives concomitantly; all others were taking no other medications. One of the subjects taking an oral contraceptive developed headache, peripheral edema, borderline arterial hypertension (144/91 mmHg), and hypokalemia (2.6 mmol/L) and discontinued treatment. Kaliuresis was noted as well, though not statistically significant. After one week, plasma renin activity significantly decreased in groups taking 380 mg and 814 mg glycyrrhizin (p=0.025 and p=0.045, respectively). Plasma aldosterone decreased significantly in the group taking 814 mg glycyrrhizin (p=0.04). This indicates that volume expansion occurred; however, renal sodium retention was not found to be significant 2.
Common questions
Can I take Licorice and Levonorgestrel together?
Increased risk of fluid retention and elevated blood pressure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Licorice and Levonorgestrel interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Licorice or Levonorgestrel need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (4)
- deKlerk G, Neiuwenhuis M, & Beutler J: Hypokalemia and hypertension associated with use of liquorice flavoured chewing gum. Br Med J 1997; 314(7082):731-732.
- Bernardi M, D'Intino PE, Trevisani F, et al: Effects of prolonged ingestion of graded doses of licorice by healthy volunteers. Life Sci 1994; 55(11):863-872. PubMed
- Kato H, Kanaoka M, Yano S, et al: 3-Monoglucuronyl-glycyrrhetinic acid is a major metabolite that causes licorice-induced pseudoaldosteronism. J Clin Endocrinol Metab 1995; 80(6):1929-1933. DOI
- Walker BR & Edwards CRW: Licorice-induced hypertension and syndromes of apparent mineralocorticoid excess. Endocrinol Metab Clin North Am 1994; 23:359-377. DOI
Keep reading about Levonorgestrel
Keep reading about Licorice
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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