Herb & supplement monograph

Henna Drug Interactions, Uses, Effectiveness, Safety & More

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

What is this page for?

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

But these pages have grown well beyond that into a full monograph — what Henna 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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Henna 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 Henna drug interaction appears low for most people. Only a single interaction is on record, it is rated moderate rather than major, and no major interactions have been documented.

Interactions deserving the most attention

The one combination that deserves real attention is lithium. Henna is thought to act as a mild diuretic, and diuretics can slow how the body clears lithium, which could raise lithium levels. Because lithium is a narrow-margin medicine where even small changes in blood levels matter, anyone taking it should treat henna with caution, and a lithium dose adjustment could become necessary if the two are combined.

What the rest of the list means

Beyond lithium, no interactions have been documented for henna, which sets it apart from many herbal products that carry long lists of theoretical concerns. Even the lithium interaction rests partly on henna's predicted diuretic effect rather than on strong, well-controlled human studies, so the true size of the effect is not firmly established. In short, henna's known interaction profile is narrow but focused on one medicine that needs close monitoring.

Check your medications against Henna

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

Interaction report

Drugs that interact with Henna

1 medication has a known interaction with Henna, 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 Henna using our pharmacist-reviewed interaction data.

AI summaries are generated from our Henna 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 Henna 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 Henna affects

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

All 1 drug category Henna interacts with

Lithium

Henna is thought to have diuretic properties. Theoretically, due to these potential diuretic effects, henna might reduce excretion and increase levels of lithium. The dose of lithium might need to be decreased.

Likelihood Probable Evidence D

Monograph

Henna: Uses, Safety & Side Effects

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

The bottom line

Henna is a plant most widely used as a natural dye for hair, skin, and nails, and has a long history in traditional medicine for skin and minor wound care. Strong human evidence for medicinal benefits is limited, and pure (natural) henna applied to skin is generally well tolerated, but so-called 'black henna' products can cause serious skin reactions. Talk to a pharmacist or doctor before using henna for any health purpose, and avoid taking it by mouth.

Scientific name: Lawsonia inermis
Family: Lythraceae
Part used: Leaves (also bark, seeds, and flowers in traditional use)
Common forms: Dried leaf powder, paste, oil, and occasionally extracts; mostly used topically for hair and skin

People commonly use it for

Hair and skin dye
Cooling and skin care
Wound and skin healing (traditional)
Antimicrobial and antifungal (traditional)
Nail and scalp conditions

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

Safety at a glance

OverallUse caution

Natural henna is generally safe applied to skin and hair, but 'black henna' and oral use can be harmful.

PregnancyUnsafe

When used orally. Henna is believed to have abortifacient properties. There is insufficient reliable information available about the safety of henna w...

Read the full pregnancy detail

BreastfeedingUnsafe

When used orally. Henna is believed to have abortifacient properties. There is insufficient reliable information available about the safety of henna w...

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

Henna comes from the leaves of the Lawsonia inermis plant, a flowering shrub that grows in hot, dry regions of North Africa, the Middle East, and South Asia. The leaves are dried and ground into a powder that is mixed with water to make a paste.

For thousands of years, people have used henna to dye hair, skin, and nails a reddish-brown color. It is famous for the decorative body art known as mehndi. Beyond its use as a dye, henna has a place in traditional medicine systems, where it has been applied to the skin for cooling, healing, and minor skin problems.

Today henna is most often used cosmetically. Medicinal use is mostly traditional and is not well supported by high-quality human studies.

How it works

The main active compound in henna is lawsone (also called hennotannic acid), a reddish-orange pigment found in the leaves. Lawsone binds to keratin, the protein in hair, skin, and nails, which is why henna creates a long-lasting stain.

Henna leaves also contain tannins, flavonoids, and other plant compounds. In laboratory studies, some of these have shown antioxidant, antimicrobial, and anti-inflammatory activity.

It is important to know that these mechanisms are mostly based on test-tube and animal research. They do not prove that henna works as a medicine when used by people.

Effectiveness

Does Henna work?

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

Evidence overview · 5 uses evaluated

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

Also studied for 5 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Chemotherapy-induced acral erythema