Drug & supplement interaction

Alfalfa + Natalizumab

Natalizumab brand name: Tysabri.

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

Alfalfa has a moderate interaction with Natalizumab. Theoretically, alfalfa might decrease the efficacy of immunosuppressive therapy.

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

Alfalfa and Natalizumab

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

Moderate

IMMUNOSUPPRESSANTS

Why this applies to Natalizumab

Natalizumab falls under IMMUNOSUPPRESSANTS — the group Alfalfa interacts with.

Theoretically, alfalfa might decrease the efficacy of immunosuppressive therapy.
In vitro research and human case reports suggest that alfalfa may have immunostimulant effects.
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. Natalizumab (Tysabri) works by calming down part of your immune system to keep multiple sclerosis flare-ups in check. Alfalfa, on the other hand, contains compounds that may gently rev up immune activity. So in theory, taking concentrated alfalfa supplements could work against what Tysabri is trying to do, possibly making it a little less effective at preventing relapses or slowing disability.

I want to be honest, though: this concern comes from lab studies and a few case reports, not from solid human trials, so it's more of a theoretical caution than a proven problem. A little alfalfa in a salad is unlikely to matter. Before starting any alfalfa supplement, please run it by your neurologist or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Light TD, Light JA. Acute renal transplant rejection possibly related to herbal medications. Am J Transplant 2003;3:1608-9. PubMed
  2. Prete PE. The mechanism of action of L-canavanine in inducing autoimmune phenomena. Arthritis Rheum 1985;28:1198-200. PubMed
  3. Alcocer-Varela J, Iglesias A, Llorente L, Alarcon-Segovia D. Effects of L-canavanine on T cells may explain the induction of systemic lupus erythematosus by alfalfa. Arthritis Rheum 1985;28:52-7. 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

Alfalfa Also Interacts With Other Medications

Alfalfa has 2 major, 580 moderate known drug interactions in our database — the Natalizumab one above is one of them. If you take anything else, check it against the full list below.

Major 2 Moderate 580 No known interaction 2,248 (incl. Natalizumab)
Taking anything else?

Check Another of Your Medications Against Alfalfa

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

From our Q&A

Questions About Alfalfa or Natalizumab

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Alfalfa or Natalizumab, 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 Natalizumab

This page covers Alfalfa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Natalizumab page lists 70 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 1 major · 59 moderate · 10 minor.

From our pharmacist’s overview on the Natalizumab page

“Natalizumab (Tysabri) works by quieting an overactive immune system in multiple sclerosis and Crohn's disease, and that is exactly why this list of 70 supplements deserves real care rather than a shrug. Fifty-three of them, ashwagandha among the familiar names, are believed to stimulate immune function, which could work directly agains…”

Reviewed by 2 · Jul 18, 2026

Open the Natalizumab interaction page

One more smart check

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

We hold 3,559 real supplement products containing Alfalfa, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Alfalfa. Your product may carry other ingredients that interact with Natalizumab too, on top of Alfalfa — 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 Alfalfa and Natalizumab 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 Alfalfa
Top 10%

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

29 days ago today
Medication Natalizumab
Top half

#1,359 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 Alfalfa

What is Alfalfa?

Alfalfa
  • High cholesterol
  • Digestive complaints
  • Menopausal symptoms
  • Arthritis and joint pain
  • General nutritional supplement

Alfalfa is a nutrient-rich legume that people use for high cholesterol, menopause symptoms, and general wellness, but solid human evidence for most of these uses is limited. It is best avoided by people with autoimmune diseases, those who are pregnant or breastfeeding, and anyone with a weakened immune system, and you should check with your pharmacist or doctor before trying it.

Read the full Alfalfa monograph & all interactions
Medication

About Natalizumab Injection

What Is Natalizumab Injection Used For?

Brand name: Tysabri

Tysabri is approved for adults with relapsing forms of multiple sclerosis — including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease. It is used as a solo therapy (monotherapy) for MS, not combined with other disease-modifying drugs.

Tysabri is also approved to induce and maintain remission in adults with moderately to severely active Crohn's disease when standard treatments and TNF-alpha inhibitors have not worked or cannot be tolerated. In Crohn's disease, it must not be combined with immunosuppressants or TNF-alpha inhibitors.

See full Natalizumab Injection drug information
Keep checking

Other Drugs & Alfalfa

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

2Major
580Moderate
0Minor
2,247No known interaction
2 Major 580 Moderate 2,247 No interaction
Major

2 interactions

Moderate

580 interactions

Showing 60 of 580 moderate interactions — see all 580 on the Alfalfa page.

No interaction 2,247 drugs checked — show the list

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

Showing the 60 most looked-up of 2,247 medications checked with no known interaction — see the full Alfalfa list.

See the full Alfalfa interactions page
See every supplement checked against Natalizumab, 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
Alfalfa monograph › Uses, safety, and every drug interaction in one place Natalizumab supplement interactions › Every supplement checked against Natalizumab, ranked by severity Natalizumab Injection 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 Alfalfa and Natalizumab Together: Common Questions

Can you take Alfalfa with Natalizumab?
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 Alfalfa and Natalizumab 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 Natalizumab and Alfalfa?

Our pharmacists answer your medication & supplement questions — free.

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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.