Herb and medicine interaction

Mulethi (licorice) and MAOI medicines

Yashtimadhu (mulethi, licorice) (Glycyrrhiza glabra) with MAOIs (tranylcypromine, phenelzine, selegiline).

Theoretical riskPending review

The short answer

Not known in people. We found no study of licorice with MAOIs in people. Memorial Sloan Kettering's licorice monograph says licorice may boost the activity of MAOIs, though the clinical relevance is not known. In a lab study cited by the European Medicines Agency, a licorice extract blocked MAO-B, one of the enzymes these medicines act on.

Licorice also raises blood pressure and lowers potassium on its own, through glycyrrhizin, its sweet compound. If you take an MAOI such as tranylcypromine or selegiline, tell your prescribing doctor before you take mulethi in any form, including teas, lozenges and cough products, and ask whether your blood pressure should be checked.

MAOIs sold in India include tranylcypromine (Trivon) and selegiline (Selgin).

At a glance

What was seenHow it may workDirectionEvidence
Possible stronger MAOI effect[1]Not establishedMAOI effect may increase; size unknownTheoretical by mechanism
Licorice extract blocked the MAO-B enzyme[2]Enzyme inhibition in the labCould add to what the MAOI doesIn vitro

No listing is not a clearance. A missing interaction here never means a combination is safe.

The evidence, study by study

Herb monograph, Memorial Sloan Kettering Theoretical by mechanism

MSK lists MAOIs among the medicines licorice may interact with, in these words: "Licorice may potentiate activity of MAOIs. Clinical relevance is not known." It gives no study, dose or size of effect for the warning.[1]

Laboratory study, 2013, cited by the EMA In vitro

The European Medicines Agency's assessment report cites a 2013 lab study by Mazzio and colleagues in which a methanol extract of licorice blocked MAO-B at low concentrations. Lab findings like this show a possible route for an interaction. They do not show that one happens in people.[2]

What your doctor may watch for

  • Blood pressure and potassium, because glycyrrhizin raises the first and lowers the second.[3]

What to tell your prescribing doctor

You can read this out, or show them this page:

“I am taking, or planning to take, mulethi (licorice) as a tea, powder, lozenge or cough product (name and how much) along with my MAOI. A monograph warns that licorice may boost MAOIs, and licorice can raise blood pressure. Is it a concern for me?”

Withheld until review

Dose adjustments and any “no known interaction” clearance appear only after a vaidya on our medical board has reviewed this page. Why we hold these back

Related

Sources

  1. Memorial Sloan Kettering Cancer Center. About Herbs: Licorice (health professional information, herb-drug interactions).
  2. European Medicines Agency, HMPC. Assessment report on Glycyrrhiza glabra L., G. inflata Bat., G. uralensis Fisch., radix. EMA/HMPC/108395/2024, revision 1.
  3. European Medicines Agency, HMPC. European Union herbal monograph on Glycyrrhiza glabra L., G. inflata Bat., G. uralensis Fisch., radix. EMA/HMPC/108399/2024, revision 1, adopted 4 March 2026. Sections 4.4 and 4.5.

Updated 4 November 2026

Taking yashtimadhu with other medicines? A vaidya can check your full list.

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