Drug & supplement interaction

Gumweed + Mitomycin

Mitomycin brand names: Mutamycin, Mitosol, Jelmyto.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Gumweed and Mitomycin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Gumweed and Mitomycin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Mitomycin and Gumweed in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Gumweed at all — not against Mitomycin, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Gumweed safety at a glance

Gumweed overall Use caution Generally used in small amounts traditionally, but human safety data are limited.
Pregnancy Avoid Not enough safety information, so it is best avoided.
Breastfeeding Avoid Safety while breastfeeding is unknown, so avoid use.

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

Still wondering about combining Mitomycin and Gumweed? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Gumweed Itself Has Been Linked To

This is not an interaction — nothing below involves Mitomycin. It is the side-effect record for Gumweed on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Gumweed, this list is the first place to look.

  • Diarrhea Additional detail

    “Orally, gumweed seems to be well tolerated. It can cause gastric mucosal irritation (2,12), diarrhea (18), and kidney irritation (12).”

    Gumweed · Natural Medicines adverse-effect record, reported in diarrhea.

    3 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    3. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    “Orally, gumweed can cause gastric mucosal irritation (2,12) and diarrhea (18).”

    Gumweed · Natural Medicines adverse-effect record, reported in diarrhea.

    3 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    3. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

Everything above comes from the Natural Medicines adverse-effect record for Gumweed — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Mitomycin’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Mitomycin column appears here.

Everything else you take

See Every Supplement That Interacts With Mitomycin

This page covers Gumweed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Mitomycin page lists 26 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Acerola (moderate), Alpha-lipoic Acid (moderate), Coffee Charcoal (moderate) and Dimethylsulfoxide (dmso) (moderate).

By severity: 1 major · 15 moderate · 10 minor.

From our pharmacist’s overview on the Mitomycin page

“Activated charcoal is the entry to know first with mitomycin (Mutamycin, Mitosol, Jelmyto), a chemotherapy drug, because charcoal binds medications and can cut the amount the body receives, and it carries this list's only major rating. A weakened dose of a cancer treatment is a real loss, so I would treat these 26 interactions with gen…”

Reviewed by 2 · Jul 18, 2026

Open the Mitomycin interaction page

One more smart check

Taking Gumweed as Part of a Dietary Supplement Product? Check It for Interactions

We hold 18 real supplement products containing Gumweed, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Gumweed. Even though Gumweed itself has no known interaction with Mitomycin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Gumweed and Mitomycin Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Gumweed
Steady interest

#1,013 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Mitomycin
Top 10%

#244 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Gumweed reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Gumweed and Mitomycin records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Gumweed

What is Gumweed?

  • Cough and bronchitis
  • Asthma-related breathing problems
  • Skin irritation from poison ivy or poison oak
  • Minor wounds and rashes
  • Upper respiratory congestion

Gumweed is a traditional North American plant used mostly for coughs, chest congestion, and skin irritation such as poison ivy rashes. Good-quality human studies are lacking, so its benefits are not well proven, and it should be used cautiously and avoided during pregnancy and breastfeeding.

Grindelia robusta · Asteraceae · Dried leaves and flowering tops · Tea, tincture, liquid extract, capsules, topical preparations

An interaction check asks whether these two react with each other — it does not ask whether Gumweed is a good idea for someone in your situation. Here is what our Gumweed record says about it on its own.

Gumweed: dosing

There is no well-established, standardized dose for gumweed. Traditional preparations include teas, tinctures, and liquid extracts, but the strength of commercial products varies widely.The safest approach is to follow the directions on the product label and not exceed the suggested amount.

From our Gumweed monograph — the full record covers uses, side effects and every documented interaction.

Read the full Gumweed monograph & all interactions
Medication

About Mitomycin

What Is Mitomycin Used For?

Brand names: Mutamycin, Mitosol, Jelmyto

Mitomycin (and its brand Mutamycin) is used intravenously in combination with other chemotherapy drugs to treat disseminated adenocarcinoma (a type of cancer that has spread) of the stomach or pancreas, when other treatments have not worked. It is not intended to replace surgery or radiation therapy.

Mitomycin is also the active ingredient in other products for different uses: Jelmyto treats low-grade upper tract urothelial cancer (cancer of the upper urinary tract); Zusduri treats recurrent low-grade intermediate-risk non-muscle invasive bladder cancer; and Mitosol is used as a surgical aid during certain glaucoma eye surgery. These are separate products with distinct indications and are not interchangeable with the intravenous injection form.

See full Mitomycin drug information
Keep checking

Other Drugs & Gumweed

Browse every other medication we’ve checked against Gumweed — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
No interaction 2,829 drugs checked — show the list
Evidence & sources

Gumweed References

The 3 references that drive our Gumweed 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.

  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Gumweed and Mitomycin Together: Common Questions

Is it safe to take Gumweed with Mitomycin?
We do not list a known interaction between Gumweed and Mitomycin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Does Mitomycin interact with any supplements?
Yes. Mitomycin has documented interactions with 26 supplements in our database — Gumweed is not one of them. The Mitomycin interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Mitomycin and Gumweed?

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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.