Herb & supplement monograph

Masterwort Drug Interactions, Uses, Safety & More

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

What is this page for?

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

But these pages have grown well beyond that into a full monograph — what Masterwort 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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Masterwort 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 Masterwort drug interaction is moderate for most people, and it centers on one issue: added sensitivity to sunlight. None of the listed interactions are rated major, but all of them are moderate and trace back to this single sun-sensitivity concern.

Interactions deserving the most attention

The combination that deserves the most attention is masterwort with photosensitizing drugs, meaning medications that make the skin more sensitive to sunlight. When taken together, the effects can add up, raising the chance of sunburn-like reactions or rashes after sun exposure. This concern is reasonably well supported by the evidence, and the combination is generally advised against, so anyone taking a medicine known to cause sun sensitivity should treat this seriously.

What the rest of the list means

Although the number of interacting medications looks large, it does not mean hundreds of separate problems. Every listed interaction reflects the same shared concern about sun sensitivity applied across many different medications. The supporting research is still limited, so the true size of the effect in everyday use is not fully known.

Check your medications against Masterwort

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

Interaction report

Drugs that interact with Masterwort

335 medications have a known interaction with Masterwort, 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 Masterwort using our pharmacist-reviewed interaction data.

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

2,830 drugs

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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 Masterwort 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 Masterwort affects

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

All 1 drug category Masterwort interacts with

Photosensitizing Drugs

The use of masterwort in conjunction with photosensitizing drugs is contraindicated due to the potential for additive photosensitizing effects.

Likelihood Probable Evidence D

Monograph

Masterwort: Uses, Safety & Side Effects

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

The bottom line

Masterwort (Heracleum sphondylium), a plant in the carrot family, has a long folk-medicine history for digestion, nerves, and skin. Modern scientific evidence to support these uses is very limited, and the plant can cause skin reactions to sunlight, so use it cautiously and talk with your pharmacist or doctor first.

Scientific name: Heracleum sphondylium
Family: Apiaceae
Part used: Root, leaves, seeds, and aerial parts
Common forms: Tea, tincture, dried herb, essential oil

People commonly use it for

Digestive upset
Mild anxiety and tension
Skin complaints
Respiratory and cough relief
Traditional tonic

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

Safety at a glance

OverallUse caution

Limited safety data exist, and the plant can cause sun-triggered skin reactions.

PregnancyBest avoided

Not enough safety information; best avoided during pregnancy.

BreastfeedingBest avoided

No reliable safety data, so avoid while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Masterwort usually refers to Heracleum sphondylium, a tall flowering plant in the carrot family (Apiaceae). It is also called cow parsnip, hogweed, and berce commune. It grows wild across Europe and parts of Asia in meadows, hedgerows, and along roadsides.

The name "masterwort" has historically been used for a few different plants, including Peucedanum ostruthium (sometimes called Imperatoria) and the garden plant Astrantia major ("great masterwort"). Because the name is shared, it is easy to confuse these plants, so it helps to check the Latin name on any product.

In traditional herbal practice, the root, leaves, and seeds have been used to make teas, tinctures, and other preparations for digestion, nerves, and skin. Today it is much less common than mainstream herbal remedies.

Uses & effectiveness

People have traditionally used masterwort for digestive complaints such as bloating, gas, and poor appetite. It has also been used as a mild remedy for nervous tension, for coughs and chest complaints, and applied to the skin for various conditions.

It is important to be honest here: high-quality human studies on masterwort are lacking. Most of what is known comes from traditional use and a small amount of laboratory research on related plants. There is not enough reliable evidence to say that masterwort effectively treats any medical condition.

If you are considering masterwort for a specific health problem, treat it as an unproven option and discuss safer, better-studied choices with a healthcare professional.

How it works

Plants in the carrot family contain compounds called furanocoumarins, along with essential oils and other plant chemicals. Laboratory studies of Heracleum species suggest these compounds may have antioxidant or mild antimicrobial activity, but this is mostly test-tube research.

Furanocoumarins are also the reason masterwort can make skin more sensitive to sunlight. When these chemicals get on the skin and are exposed to sun, they can trigger a burn-like rash. This is a known effect of several Apiaceae plants.

Overall, the exact way masterwort might affect the body in people is not well understood, and proposed benefits should be seen as preliminary.

Safety & precautions

The biggest known concern with masterwort and related hogweeds is phototoxicity. Contact with the sap followed by sun exposure can cause redness, blistering, and burns on the skin. Handle the fresh plant with care and protect treated skin from the sun.

People with allergies to other carrot-family plants (such as celery, carrot, fennel, or dill) may be more likely to react to masterwort. Anyone with sensitive skin or a history of plant rashes should be especially careful.

Pregnancy and breastfeeding: There is not enough safety information for either situation. Because some carrot-family plants can affect the body in ways that may not be safe during pregnancy, masterwort should be avoided if you are pregnant or breastfeeding.

Always tell your pharmacist or doctor about any herbal product you are using, especially if you have a chronic condition or take other medicines.

Side effects

The most commonly reported problem is a skin reaction to sunlight (phototoxic dermatitis) after contact with the plant or its sap. This can range from mild redness to painful blisters.

When taken by mouth, possible side effects are not well documented but could include stomach upset or allergic reactions, particularly in people sensitive to carrot-family plants. Stop using it and seek care if you develop a rash, swelling, or trouble breathing.

Dosing

There is no standardized, well-established dose for masterwort. Traditional preparations vary widely, and product strengths are not consistent.

If you choose to use a commercial product, follow the directions on the label and do not exceed the suggested amount. Because reliable dosing and safety data are limited, it is best to check with a pharmacist or doctor before starting, especially if you are taking other medicines or have a health condition.

References & further reading

The 1 references that drive our Masterwort monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

Pharmacist Counseling Corner

Masterwort: Common Questions

Does Masterwort interact with prescription medications?

Yes. We list 335 medications with a known interaction with Masterwort. Use the checker above to see how Masterwort interacts with a specific drug.

How are Masterwort interactions rated?

Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.

Is it safe to take Masterwort with my medications?

It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.

Where does this Masterwort interaction information come from?

Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.

What is Masterwort used for?

Traditionally it has been used for digestive upset, mild nervous tension, coughs, and skin complaints. These uses come from folk medicine, and there is not enough scientific evidence to confirm that it works.

Is Masterwort safe?

Safety data are limited. The main known risk is a skin reaction triggered by sunlight after contact with the plant, so it should be used cautiously and with guidance from a healthcare professional.

Can I take Masterwort while pregnant or breastfeeding?

No. There is not enough reliable safety information, so Masterwort is best avoided during pregnancy and breastfeeding.

Is Masterwort the same as the garden plant Astrantia major?

Not exactly. The name "Masterwort" is used for several plants, including Heracleum sphondylium, Peucedanum ostruthium, and the ornamental Astrantia major, so always check the Latin name on a product.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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