Drug & supplement interaction

Lactobacillus Gasseri + Methotrexate

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

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Lactobacillus Gasseri and Methotrexate 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

Lactobacillus Gasseri and Methotrexate

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 Methotrexate and Lactobacillus Gasseri 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.

Lactobacillus Gasseri safety at a glance

Lactobacillus Gass... overall Use caution Generally well tolerated in healthy adults, but evidence is limited and some people should avoid it.
Pregnancy Use caution Not enough reliable safety data; use only with a doctor's guidance.
Breastfeeding Use caution Limited safety information, so check with your doctor before using.

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

Still wondering about combining Methotrexate and Lactobacillus Gasseri? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Methotrexate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Methotrexate is filed under 6 classifications — including organic anion-transporting polypeptide substrates (oatp), organic anion transporter 3 (oat3) substrates, hepatotoxic drugs. Lactobacillus Gasseri has documented interactions with 1 drug class — the most serious being antibiotic drugs (moderate) — and none of Methotrexate’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

Lactobacillus Gasseri Does Interact With Other Medications

Lactobacillus Gasseri has 182 moderate known drug interactions in our database — Methotrexate isn’t one of them. If you take anything else, check it against the full list below.

Moderate 182 No known interaction 2,648 (incl. Methotrexate)
Taking anything else?

Check Another of Your Medications Against Lactobacillus Gasseri

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

What to actually watch for

No Interaction Found — But Data Suggests Lactobacillus Gasseri and Methotrexate 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. One of them is worth acting on rather than waiting out — marked below.

  • A higher chance of infection Worth acting on Additional detail

    Lactobacillus Gasseri

    “Since Lactobacillus gasseri preparations contain live and active microorganisms, there is some concern that they might cause pathogenic infection in some patients. Some lactobacilli species have been isolated in cases of bacteremia, sepsis, splenic abscess, endocarditis, necrotizing fasciitis, pancreatic necrosis, and meningoencephalitis.”

    Lactobacillus Gasseri · Natural Medicines adverse-effect record, reported in cirrhosis.

    6 sources cited
    1. 107543. Rossi F, Amadoro C, Gasperi M, Colavita G. Lactobacilli infection case reports in the last three years and safety implications. Nutrients. 2022;14(6):1178. PubMed
    2. 110917. Ranchal P, Gupta R, Goldberg R, A Lobo S, Pascual A, El Khoury MY. Penicillin-sensitive Lactobacillus jensenii bacteremia. Am J Ther 2021;28(2):e250-e252. PubMed
    3. 110918. Grazioli-Gauthier L, Rigamonti E, Leo LA, Martinetti Lucchini G, Lo Priore E, Bernasconi E. Lactobacillus jensenii mitral valve endocarditis: Case report, literature review and new perspectives. IDCases 2022;27:e01401. PubMed
    4. 110920. Toprak NU, Bozan T, Yilmaz S, Buyukbayrak EE, Tigen ET. Polymicrobial bacteremia due to Lactobacillus jensenii and Veillonella montpellierensis in a pregnant patient; case report and review of literature. Anaerobe 2022;75:102576. PubMed
    5. 110921. Chazan B, Raz R, Shental Y, Sprecher H, Colodner R. Bacteremia and pyelonephritis caused by Lactobacillus jensenii in a patient with urolithiasis. Isr Med Assoc J 2008;10(2):164-5.
    6. 112579. Ramos-Coria D, Canto-Losa J, Carrillo-Vázquez D, Carbajal-Morelos L, Estrada-León R, Corona-Rodarte E. Lactobacillus gasseri liver abscess and bacteremia: a case report. BMC Infect Dis 2021;21(1):518. PubMed

    Methotrexate

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

Effects for Methotrexate come from the ADVERSE REACTIONS section of its FDA label; effects for Lactobacillus Gasseri come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 489,806 voluntary FDA FAERS reports for Methotrexate 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.

From our Q&A

Questions About Lactobacillus Gasseri 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 Lactobacillus Gasseri 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 Lactobacillus Gasseri 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 Lactobacillus Gasseri as Part of a Dietary Supplement Product? Check It for Interactions

We hold 852 real supplement products containing Lactobacillus Gasseri, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lactobacillus Gasseri. Even though Lactobacillus Gasseri itself has no known interaction with Methotrexate, 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 Lactobacillus Gasseri 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 Lactobacillus Gasseri
Top 25%

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

29 days ago today
Medication Methotrexate
Top 5%

#49 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 Lactobacillus Gasseri reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Lactobacillus Gasseri and Methotrexate 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 Lactobacillus Gasseri

What is Lactobacillus Gasseri?

  • Digestive health
  • Weight and belly fat management
  • Vaginal and urinary health
  • Bloating and gut discomfort
  • General immune support

Lactobacillus gasseri is a 'friendly' probiotic bacterium found naturally in the human gut, mouth, and vaginal tract, and in some fermented foods. Early research suggests it may help with digestion, weight management, and vaginal health, but the evidence is limited and far from conclusive. It is generally well tolerated in healthy people, but anyone who is pregnant, breastfeeding, or has a weakened immune system should talk to a pharmacist or doctor first.

Lactobacillus gasseri · Lactobacillaceae · Live bacterial cells (probiotic strain) · Capsules, tablets, powders, fermented dairy products, and combination probiotic supplements

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

Lactobacillus Gasseri: dosing

There is no official standardized dose of L. gasseri. Probiotic amounts are usually measured in colony-forming units (CFUs), and products vary widely.The best approach is to follow the directions on the product label and not exceed the recommended amount.

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

Read the full Lactobacillus Gasseri 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.

Most-Reported Side Effects for Methotrexate

From FAERS, the FDA’s public side-effect reporting system (489,806 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Rheumatoid arthritis 42,798 reports
Arthralgia 40,830 reports
Fatigue 33,049 reports
Nausea 28,999 reports
Joint swelling 25,026 reports
See full Methotrexate drug information
Keep checking

Other Drugs & Lactobacillus Gasseri

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

0Major
182Moderate
0Minor
2,647No known interaction
182 Moderate 2,647 No interaction
Moderate

182 interactions

Showing 60 of 182 moderate interactions — see all 182 on the Lactobacillus Gasseri page.

No interaction 2,647 drugs checked — show the list

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

Showing the 60 most looked-up of 2,647 medications checked with no known interaction — see the full Lactobacillus Gasseri list.

See the full Lactobacillus Gasseri interactions page
See every supplement checked against Methotrexate, ranked by severity
Evidence & sources

Lactobacillus Gasseri References

The 12 references that drive our Lactobacillus Gasseri 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. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.
  2. Ramachandran L, Dontaraju VS, Patel K. Lactobacillus-associated spontaneous bacterial peritonitis in a liver cirrhosis patient on probiotics. Cureus. 2020;12(12):e11896. PubMed
  3. Rossi F, Amadoro C, Gasperi M, Colavita G. Lactobacilli infection case reports in the last three years and safety implications. Nutrients. 2022;14(6):1178. PubMed
  4. Ranchal P, Gupta R, Goldberg R, A Lobo S, Pascual A, El Khoury MY. Penicillin-sensitive Lactobacillus jensenii bacteremia. Am J Ther 2021;28(2):e250-e252. PubMed
  5. Grazioli-Gauthier L, Rigamonti E, Leo LA, Martinetti Lucchini G, Lo Priore E, Bernasconi E. Lactobacillus jensenii mitral valve endocarditis: Case report, literature review and new perspectives. IDCases 2022;27:e01401. PubMed
  6. Toprak NU, Bozan T, Yilmaz S, Buyukbayrak EE, Tigen ET. Polymicrobial bacteremia due to Lactobacillus jensenii and Veillonella montpellierensis in a pregnant patient; case report and review of literature. Anaerobe 2022;75:102576. PubMed
  7. Chazan B, Raz R, Shental Y, Sprecher H, Colodner R. Bacteremia and pyelonephritis caused by Lactobacillus jensenii in a patient with urolithiasis. Isr Med Assoc J 2008;10(2):164-5.
  8. Ramos-Coria D, Canto-Losa J, Carrillo-Vázquez D, Carbajal-Morelos L, Estrada-León R, Corona-Rodarte E. Lactobacillus gasseri liver abscess and bacteremia: a case report. BMC Infect Dis 2021;21(1):518. PubMed
  9. Elikowski W, Malek-Elikowska M, Lisiecka M, Bodora A, Wisniewska K, Oko-Sarnowska Z. Lactobacillus gasseri endocarditis on the aortic valve bioprosthesis - a case report. Pol Merkur Lekarski 2017;43(257):220-223.
  10. Esquibel A, Dababneh AS, Palraj BR. Lactobacillus gasseri causing bilateral empyema. Case Rep Infect Dis 2017;2017:4895619.
  11. Tleyjeh IM, Routh J, Qutub MO, Lischer G, Liang KV, Baddour LM. Lactobacillus gasseri causing Fournier's gangrene. Scand J Infect Dis 2004;36(6-7):501-3. PubMed
  12. Dickgiesser U, Weiss N, Fritsche D. Lactobacillus gasseri as the cause of septic urinary infection. Infection 1984;12(1):14-6. PubMed

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 Lactobacillus Gasseri and Methotrexate Together: Common Questions

Is it safe to take Lactobacillus Gasseri with Methotrexate?
We do not list a known interaction between Lactobacillus Gasseri and Methotrexate. 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 Lactobacillus Gasseri and Methotrexate 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 Lactobacillus Gasseri and Methotrexate combination checked?
Interactions in our licensed database are recorded against drug classes. Methotrexate is filed under 6 classifications, and Lactobacillus Gasseri has documented interactions with 1 drug class — none of Methotrexate'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 Lactobacillus Gasseri interact with any other medications?
Yes. Lactobacillus Gasseri has 182 documented drug interactions in our database — Methotrexate 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 Methotrexate interact with any supplements?
Yes. Methotrexate has documented interactions with 82 supplements in our database — Lactobacillus Gasseri is not one of them. The Methotrexate 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

Lactobacillus Gasseri monograph Uses, safety profile, and every drug interaction in one place Methotrexate drug information The full plain-English guide to this medication Methotrexate supplement interactions Every supplement checked against Methotrexate, 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 12 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Methotrexate and Lactobacillus Gasseri?

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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.