Herb & supplement monograph

Marshmallow Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated June 2026

What is this page for?

First and foremost: how Marshmallow interacts with medications. The heart of this page is the interaction list — every drug Marshmallow is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Marshmallow is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Marshmallow Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Marshmallow drug interaction appears low for most people. None of the listed interactions are rated major, and nearly all are minor, with only one moderate concern in the whole profile.

Interactions deserving the most attention

The combination that deserves the most attention is lithium, a medicine with a narrow safety margin. Because marshmallow may act as a mild diuretic, it could theoretically reduce how well the body clears lithium and raise its levels, so anyone taking lithium should have this combination reviewed. Beyond that, marshmallow's mucilage, a gel-like fiber, may slow the absorption of oral medications taken at the same time, which matters most for medicines that need steady blood levels.

What the rest of the list means

The long list of interactions can look worrying, but it mostly reflects one theoretical idea, that mucilage could affect drug absorption, applied across many oral medicines rather than proven problems with each one. A suggested effect on blood thinners comes from animal research on the marshmallow flower, a part rarely used in supplements, and has not been shown to occur in people.

Check your medications against Marshmallow

Based on HelloPharmacist’s Marshmallow interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Marshmallow

2040 medications have a known interaction with Marshmallow, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Marshmallow using our pharmacist-reviewed interaction data.

AI summaries are generated from our Marshmallow interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Marshmallow combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Marshmallow affects

Every type of medication (drug category) Marshmallow is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Marshmallow interacts with

LithiumAnticoagulant/antiplatelet DrugsOral Drugs

Lithium

Theoretically, due to potential diuretic effects, marshmallow might reduce excretion and increase levels of lithium.
Marshmallow is thought to have diuretic properties. To avoid lithium toxicity, the dose of lithium might need to be decreased when used with marshmallow.

Likelihood Probable Evidence D

Anticoagulant/Antiplatelet Drugs

Theoretically, marshmallow flower might have antiplatelet effects.
Animal research suggests that marshmallow flower extract has antiplatelet effects. However, the root and leaf of marshmallow, not the flower, are the plant parts most commonly found in dietary supplements. Theoretically, use of marshmallow flower with anticoagulant/antiplatelet drugs can have additive effects, and might increase the risk for bleeding in some patients.

Likelihood Unlikely Evidence D

Oral Drugs

Theoretically, mucilage in marshmallow might impair absorption of oral drugs.
Marshmallow contains mucilage which can affect oral drug absorption. To avoid changes in absorption, take marshmallow 30-60 minutes after oral medications.

Likelihood Possible Evidence D

Monograph

Marshmallow: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed June 2026 ·

The bottom line

Marshmallow root is a traditional herb rich in soothing, gel-like fibers called mucilage, which is why it has long been used for coughs, sore throats, and stomach irritation. Evidence for these uses is mostly traditional and preliminary, but it is generally considered gentle and well-tolerated for short-term use. As with any supplement, check with your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or taking other medicines.

Scientific name: Althaea officinalis
Family: Malvaceae
Part used: Root and leaves
Common forms: Tea, capsules, tinctures, syrups, lozenges, dried root, topical creams

People commonly use it for

Cough and sore throat
Dry mouth and throat irritation
Digestive upset and heartburn
Skin irritation
Soothing inflamed tissue

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally well tolerated for short-term use, but human safety data are limited.

PregnancyInsufficient reliable information

Insufficient reliable information available.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Marshmallow (Althaea officinalis) is a flowering plant native to Europe, Western Asia, and North Africa. It grows in damp, marshy areas, which is how it got its name. It is not the same as the sugary marshmallow candy, although the candy was originally made using the plant's root long ago.

Both the root and the leaves are used in herbal preparations. The plant contains a sticky, gel-like substance called mucilage, which is thought to coat and soothe tissues. Today marshmallow is sold as teas, capsules, syrups, lozenges, tinctures, and skin creams.

In traditional and folk medicine, marshmallow has been used to calm coughs and sore throats, ease digestive discomfort, and soothe irritated skin.

How it works

The main active ingredients in marshmallow are mucilage polysaccharides — long, sugar-based fibers that swell into a thick, slippery gel when mixed with water. This gel is thought to form a protective, soothing coating over the lining of the throat, mouth, and digestive tract.

Researchers believe this coating action may help calm the urge to cough and reduce the feeling of irritation. Marshmallow also contains plant compounds called flavonoids that may have mild anti-inflammatory and antioxidant effects in laboratory tests.

It is important to know that much of this understanding comes from laboratory and animal studies. The way it behaves in the human body has not been fully studied.

Effectiveness

Does Marshmallow work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 11 uses evaluated

11 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Marshmallow, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 11 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate ACE inhibitor-induced cough