Drug & supplement interaction

Carob + Methotrexate

Methotrexate brand names: Rheumatrex, Otrexup, Rasuvo, Reditrex.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Carob has a minor interaction with Methotrexate. Theoretically, carob might also impair the absorption of oral drugs.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Carob and Methotrexate

Here is the interaction we found between these two, with the evidence behind it.

Minor

ORAL DRUGS

Why this applies to Methotrexate

Methotrexate falls under ORAL DRUGS — the group Carob interacts with.

Theoretically, carob might also impair the absorption of oral drugs.
Laboratory research shows that carob, when consumed as part of the diet or used as a thickening agent in infant formula, reduces the absorption of certain minerals. Take carob 30-60 minutes after oral medications.
Severity Minor Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist for oral methotrexate (like Trexall tablets): carob is rich in fiber and tannins, and lab studies hint that these can grab onto things in your gut and slow how much gets absorbed. The worry is that if carob and your methotrexate dose share the same window, a little less of the drug might make it into your system. For something you're taking to control rheumatoid arthritis or psoriasis, weaker absorption could mean less symptom relief.

I want to be honest, though: this is theoretical and only based on test-tube and animal-type research, not real patient studies, so I wouldn't lose sleep over it. A simple habit helps, take your methotrexate first and wait 30 to 60 minutes before having carob. And always loop in your doctor or pharmacist before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bosscher, D., Caillie-Bertrand, M., and Deelstra, H. Effect of thickening agents, based on soluble dietary fiber, on the availability of calcium, iron, and zinc from infant formulas. Nutrition 2001;17(7-8):614-618. PubMed
  2. Harmuth-Hoene, A. E. and Schelenz, R. Effect of dietary fiber on mineral absorption in growing rats. J Nutr 1980;110(9):1774-1784. PubMed
  3. Bosscher D, Van Caillie-Bertrand M, Van Cauwenbergh R, Deelstra H. Availabilities of calcium, iron, and zinc from dairy infant formulas is affected by soluble dietary fibers and modified starch fractions. Nutrition. 2003;19(7-8):641-5. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Carob Also Interacts With Other Medications

Carob has 2,021 minor known drug interactions in our database — the Methotrexate one above is one of them. If you take anything else, check it against the full list below.

Minor 2,021 No known interaction 809 (incl. Methotrexate)
Taking anything else?

Check Another of Your Medications Against Carob

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

From our Q&A

Questions About Carob or Methotrexate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Carob or Methotrexate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Methotrexate

This page covers Carob only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methotrexate page lists 82 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Beer (major), Grapefruit (major) and Siberian Cocklebur (major).

By severity: 7 major · 60 moderate · 15 minor.

From our pharmacist’s overview on the Methotrexate page

“The liver is where methotrexate and supplements clash most. Methotrexate (Rheumatrex, Otrexup, Rasuvo), used for rheumatoid arthritis, psoriasis, and certain cancers, can strain the liver on its own, and 38 of the 82 interacting ingredients on this list add liver risk of their own, alcohol included, which makes this a list to approach…”

Reviewed by 2 · Jul 18, 2026

Open the Methotrexate interaction page

One more smart check

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

We hold 161 real supplement products containing Carob, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Carob. Your product may carry other ingredients that interact with Methotrexate too, on top of Carob — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Carob and Methotrexate 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 Carob
Top half

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

29 days ago today
Medication Methotrexate
Top 5%

#44 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.

Supplement

About Carob

What is Carob?

Carob
  • Diarrhea (especially in children)
  • Cocoa/chocolate substitute
  • Digestive upset
  • Acid reflux/heartburn
  • Source of dietary fiber

Carob is a Mediterranean tree whose pods are widely used as a caffeine-free, naturally sweet cocoa alternative and as a thickener (carob gum). It is mostly eaten as a food and is generally well tolerated, and carob pod preparations have some traditional and limited research use for diarrhea, but evidence for most medicinal claims is limited. Check with your pharmacist or doctor before using it as a treatment, especially for infants or children.

Read the full Carob monograph & all interactions
Medication

About Methotrexate

What Is Methotrexate Used For?

Brand names: Rheumatrex, Otrexup, Rasuvo, Reditrex

Methotrexate treats a wide range of serious conditions. In cancer care, it is used for acute lymphoblastic leukemia, non-Hodgkin lymphoma, osteosarcoma, breast cancer, head and neck cancer, and gestational trophoblastic neoplasia (a rare tumor related to pregnancy). It is also used to prevent and treat meningeal leukemia (cancer affecting the lining of the brain and spinal cord).

Outside of cancer, methotrexate is prescribed for adults with rheumatoid arthritis (RA), children with polyarticular juvenile idiopathic arthritis (a form of childhood arthritis), and adults with severe psoriasis that hasn't responded well to other treatments.

See full Methotrexate drug information
Keep checking

Other Drugs & Carob

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

0Major
0Moderate
2,021Minor
808No known interaction
2,021 Minor 808 No interaction
Minor

2,021 interactions

Showing 60 of 2,021 minor interactions — see all 2,021 on the Carob page.

No interaction 808 drugs checked — show the list

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

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Carob list.

See the full Carob interactions page
See every supplement checked against Methotrexate, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

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.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Carob monograph › Uses, safety, and every drug interaction in one place Methotrexate supplement interactions › Every supplement checked against Methotrexate, ranked by severity Methotrexate drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Carob and Methotrexate Together: Common Questions

Can you take Carob with Methotrexate?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Carob and Methotrexate interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Methotrexate and Carob?

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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.