Drug & supplement interaction

Mountain Ash + Guselkumab

Guselkumab brand name: Tremfya.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Mountain Ash and Guselkumab 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. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Mountain Ash and Guselkumab

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 Guselkumab and Mountain Ash 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.

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.

Mountain Ash safety at a glance

Mountain Ash overall Use caution Cooked berries are generally well tolerated in food amounts, but raw berries can cause stomach upset and evidence for medicinal use is limited.
Pregnancy Possibly Unsafe When large amounts of fresh berries are ingested. There is insufficient reliable information available about the safety of dried or cooked berries; avoid using. Read the full pregnancy detail
Breastfeeding Possibly Unsafe When large amounts of fresh berries are ingested. There is insufficient reliable information available about the safety of dried or cooked berries; avoid using. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Guselkumab and Mountain Ash? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Guselkumab

Interactions in our licensed database are recorded against drug classes, not just single drug names. Guselkumab is filed under a single classification — immunosuppressants. Mountain Ash has documented interactions with 1 drug class — the most serious being nephrotoxic drugs (moderate) — and none of Guselkumab’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Mountain Ash Does Interact With Other Medications

Mountain Ash has 355 moderate known drug interactions in our database — Guselkumab isn’t one of them. If you take anything else, check it against the full list below.

Moderate 355 No known interaction 2,475 (incl. Guselkumab)
Taking anything else?

Check Another of Your Medications Against Mountain Ash

Covers the 2,830 medications we’ve checked against Mountain Ash. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Mountain Ash and Guselkumab May Share a Side Effect

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Diarrhea Additional detail

    Mountain Ash

    “Orally, consuming large amounts of fresh mountain ash berries can cause serious adverse effects due to its parasorbic acid constituent. These adverse effects include gastroenteritis, vomiting, queasiness, gastric pain, diarrhea, kidney damage, and polymorphic xanthomas (18).”

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

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    “Orally, large amounts of fresh mountain ash berries may cause gastroenteritis, vomiting, queasiness, gastric pain, and diarrhea due to its parasorbic acid constituent (18).”

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

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Guselkumab

    Listed in the ADVERSE REACTIONS section of the FDA label for Guselkumab. Read the label on DailyMed ›

Reported for Mountain Ash but not commonly for Guselkumab: kidney problems, nausea and vomiting.

Effects for Guselkumab come from the ADVERSE REACTIONS section of its FDA label; effects for Mountain Ash come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 35,559 voluntary FDA FAERS reports for Guselkumab that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Mountain Ash in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When large amounts of fresh berries are ingested. There is insufficient reliable information available about the safety of dried or cooked berries; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Everything else you take

See Every Supplement That Interacts With Guselkumab

This page covers Mountain Ash only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guselkumab page lists 53 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Active Hexose Correlated Compound (ahcc) (moderate), Alfalfa (moderate), American Ginseng (moderate), Andrographis (moderate) and Ashwagandha (moderate).

By severity: 52 moderate · 1 minor.

From our pharmacist’s overview on the Guselkumab page

“Guselkumab (Tremfya) quiets an overactive branch of the immune system to control psoriasis and psoriatic arthritis, and all 53 supplements on this list interact the same way, by potentially revving that system back up. None is rated major, 52 are moderate and one is minor, so for most people this reads as a watch list rather than a sto…”

Reviewed by 2 · Jul 18, 2026

Open the Guselkumab interaction page

One more smart check

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

We hold 1 real supplement products containing Mountain Ash, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Mountain Ash. Even though Mountain Ash itself has no known interaction with Guselkumab, 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 Mountain Ash and Guselkumab 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 Mountain Ash
Steady interest

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

29 days ago today
Medication Guselkumab
Steady interest

#2,392 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 Mountain Ash reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Mountain Ash and Guselkumab 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 Mountain Ash

What is Mountain Ash?

Mountain Ash
  • Sore throat and hoarseness
  • Digestive upset and constipation
  • Cough and chest congestion
  • Mild urinary complaints
  • Source of vitamin C in folk medicine

Mountain ash (rowan) is a northern-hemisphere tree whose bright red berries are traditionally cooked into jams, syrups, and teas. There is very little reliable human research to support any medical use, and raw berries contain compounds that can cause stomach upset, so cooking is important. If you want to try it, talk with your pharmacist or doctor first.

Sorbus aucuparia · Rosaceae · Fruit (berries), and sometimes the flowers and bark · Cooked berries, jam or jelly, juice, syrup, tea, tincture

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

Mountain Ash: dosing

There is no established or standardized medicinal dose for mountain ash. It is most often consumed as cooked berries, jam, syrup, or tea rather than as a measured supplement.If you use a commercial product, follow the directions on the label and do not exceed the suggested amount.

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

Read the full Mountain Ash monograph & all interactions
Medication

About Guselkumab Injection

What Is Guselkumab Injection Used For?

Brand name: Tremfya

Tremfya (guselkumab) injection treats four conditions. For plaque psoriasis and psoriatic arthritis, Tremfya is approved for adults and children 6 years and older who weigh at least 40 kg (about 88 lbs) and who need systemic therapy or phototherapy. For ulcerative colitis and Crohn's disease, Tremfya is approved for adults with moderately to severely active disease.

For ulcerative colitis and Crohn's disease, Tremfya may be given by intravenous (IV) infusion during the initial treatment phase, then switched to subcutaneous (under-the-skin) injections for ongoing maintenance. For plaque psoriasis and psoriatic arthritis, Tremfya is given as subcutaneous injections only.

Most-Reported Side Effects for Guselkumab

From FAERS, the FDA’s public side-effect reporting system (35,559 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Needle issue 2,305 reports
Psoriasis 2,239 reports
Device issue 1,980 reports
Device malfunction 1,655 reports
Device deployment issue 1,495 reports
See full Guselkumab Injection drug information
Keep checking

Other Drugs & Mountain Ash

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

0Major
355Moderate
0Minor
2,474No known interaction
355 Moderate 2,474 No interaction
Moderate

355 interactions

Showing 60 of 355 moderate interactions — see all 355 on the Mountain Ash page.

No interaction 2,474 drugs checked — show the list

We also checked Mountain Ash against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,474 medications checked with no known interaction — see the full Mountain Ash list.

See the full Mountain Ash interactions page
See every supplement checked against Guselkumab, ranked by severity
Evidence & sources

Mountain Ash References

The 1 references that drive our Mountain Ash 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. 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 Mountain Ash and Guselkumab Together: Common Questions

Is it safe to take Mountain Ash with Guselkumab?
We do not list a known interaction between Mountain Ash and Guselkumab. 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.
Do Mountain Ash and Guselkumab have any of the same side effects?
Yes — our sources link each of them separately to one of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Mountain Ash and Guselkumab combination checked?
Interactions in our licensed database are recorded against drug classes. Guselkumab is filed under 1 classification, and Mountain Ash has documented interactions with 1 drug class — none of Guselkumab's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Mountain Ash interact with any other medications?
Yes. Mountain Ash has 355 documented drug interactions in our database — Guselkumab is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Guselkumab interact with any supplements?
Yes. Guselkumab has documented interactions with 53 supplements in our database — Mountain Ash is not one of them. The Guselkumab interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Mountain Ash monograph Uses, safety profile, and every drug interaction in one place Guselkumab Injection drug information The full plain-English guide to this medication Guselkumab supplement interactions Every supplement checked against Guselkumab, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Guselkumab and Mountain Ash?

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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.