Drug & supplement interaction

Larch Arabinogalactan + 6-Mercaptopurine

6-Mercaptopurine brand name: Purinethol.

Moderate Interaction
Medically reviewed by · Updated October 2026
The bottom line Moderate

Larch Arabinogalactan has a moderate interaction with 6-Mercaptopurine. Theoretically, larch arabinogalactan might interfere with immunosuppression therapy due to immunostimulant effects.

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

Larch Arabinogalactan and 6-Mercaptopurine

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

Moderate

IMMUNOSUPPRESSANTS

Why this applies to 6-Mercaptopurine

6-Mercaptopurine falls under IMMUNOSUPPRESSANTS — the group Larch Arabinogalactan interacts with.

Theoretically, larch arabinogalactan might interfere with immunosuppression therapy due to immunostimulant effects. Immunosuppressant drugs include azathioprine (Imuran), basiliximab (Simulect), cyclosporine (Neoral, Sandimmune), daclizumab (Zenapax), muromonab-CD3 (OKT3, Orthoclone OKT3), mycophenolate (CellCept), tacrolimus (FK506, Prograf), sirolimus (Rapamune), prednisone (Deltasone, Orasone), corticosteroids (glucocorticoids), and other drugs.
Severity Moderate 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 idea behind this one. 6-Mercaptopurine works in part by calming down or suppressing certain immune cells, which is why it's used in leukemia and some autoimmune conditions. Larch arabinogalactan, on the other hand, is studied as an immune supporter. So in theory, if the supplement nudges your immune system to be more active, it could work against what your medication is trying to do, possibly making the treatment less effective.

I want to be honest with you though: this is a theoretical concern based on how each one is thought to behave, not on real cases or solid studies. We just don't have proof it actually happens in people. Because 6-mercaptopurine is a serious medication used for serious conditions, please don't add this supplement without first checking with your oncologist or pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. D'Adamo P. Larch arabinogalactan. J Naturopath Med 1996;6:33-7.
  2. Kelly GS. Larch arabinogalactan: Clinical relevance of a novel immune-enhancing polysaccharide. Alt Med Rev 1999;4:96-103.
  3. Dion C, Chappuis E, Ripoll C. Does larch arabinogalactan enhance immune function? A review of mechanistic and clinical trials. Nutr Metab (Lond) 2016;13:28. 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

Larch Arabinogalactan Also Interacts With Other Medications

Larch Arabinogalactan has 120 moderate known drug interactions in our database — the 6-Mercaptopurine one above is one of them. If you take anything else, check it against the full list below.

Moderate 120 No known interaction 2,710 (incl. 6-Mercaptopurine)
Taking anything else?

Check Another of Your Medications Against Larch Arabinogalactan

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

From our Q&A

Questions About Larch Arabinogalactan or 6-Mercaptopurine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Larch Arabinogalactan or 6-Mercaptopurine, 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 6-Mercaptopurine

This page covers Larch Arabinogalactan only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the 6-Mercaptopurine page lists 106 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Active Hexose Correlated Compound (ahcc) (moderate).

By severity: 4 major · 92 moderate · 10 minor.

From our pharmacist’s overview on the 6-Mercaptopurine page

“6-Mercaptopurine (Purinethol) works by dialing down your immune system, whether for leukemia or inflammatory bowel disease, and that makes this a list to check with real care. The four major-rated entries come first.”

Reviewed by 2 · Jul 18, 2026

Open the 6-Mercaptopurine interaction page

One more smart check

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

We hold 717 real supplement products containing Larch Arabinogalactan, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Larch Arabinogalactan. Your product may carry other ingredients that interact with 6-Mercaptopurine too, on top of Larch Arabinogalactan — 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 Larch Arabinogalactan and 6-Mercaptopurine 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 Larch Arabinogalactan
Top 25%

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

29 days ago today
Medication 6-Mercaptopurine
Top half

#723 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 Larch Arabinogalactan

What is Larch Arabinogalactan?

  • Immune support
  • Cold and flu prevention
  • Digestive and gut health
  • Source of soluble fiber
  • Prebiotic support

Larch arabinogalactan is a soluble fiber from larch trees that is mainly used as a prebiotic and for immune support. Early research is interesting but limited, and most claims are not yet firmly proven. It is generally well tolerated, but pregnant and breastfeeding people should be cautious and check with a healthcare provider first.

Read the full Larch Arabinogalactan monograph & all interactions
Medication

About Mercaptopurine

What Is Mercaptopurine Used For?

Brand name: Purinethol

Mercaptopurine — available as a tablet and as an oral suspension — is used to treat acute lymphoblastic leukemia (ALL), a type of blood cancer. It is given as part of a combination chemotherapy maintenance regimen, meaning it works alongside other cancer medicines to keep leukemia in remission.

Both the tablet form and the oral suspension form carry this indication for adult and pediatric patients. The oral suspension is particularly useful for patients who cannot swallow tablets.

See full Mercaptopurine drug information Mercaptopurine NDC codes and packages
Keep checking

Other Drugs & Larch Arabinogalactan

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

0Major
120Moderate
0Minor
2,709No known interaction
120 Moderate 2,709 No interaction
Moderate

120 interactions

Showing 60 of 120 moderate interactions — see all 120 on the Larch Arabinogalactan page.

No interaction 2,709 drugs checked — show the list

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

Showing the 60 most looked-up of 2,709 medications checked with no known interaction — see the full Larch Arabinogalactan list.

See the full Larch Arabinogalactan interactions page
See every supplement checked against 6-Mercaptopurine, 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
Larch Arabinogalactan monograph › Uses, safety, and every drug interaction in one place 6-Mercaptopurine supplement interactions › Every supplement checked against 6-Mercaptopurine, ranked by severity Mercaptopurine drug information › The full plain-English guide to this medication Mercaptopurine NDC codes and packages › Every package, labeler and price in the FDA directory 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 Larch Arabinogalactan and 6-Mercaptopurine Together: Common Questions

Can you take Larch Arabinogalactan with 6-Mercaptopurine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Larch Arabinogalactan and 6-Mercaptopurine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About 6-Mercaptopurine and Larch Arabinogalactan?

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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.