Drug & supplement interaction

Alfalfa + Tositumomab

Tositumomab brand name: Bexxar.

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

Alfalfa has a moderate interaction with Tositumomab. 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 Tositumomab

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

Moderate

IMMUNOSUPPRESSANTS

Why this applies to Tositumomab

Tositumomab 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 concern with pairing alfalfa and Tositumomab (Bexxar). Tositumomab is a cancer therapy that works alongside a calmed-down immune system, so revving up the immune response usually isn't what you want during treatment. Alfalfa contains compounds that may act as a mild immune stimulant, and in theory that could work against this kind of therapy.

I'll be honest with you: this is a theoretical caution based on lab studies and a few case reports, not strong human evidence with this specific drug. Still, when you're going through a treatment like Bexxar, it's not worth the gamble. Concentrated alfalfa supplements are the real worry here, not an occasional sprout on a sandwich. Please run it by your oncologist or pharmacist before adding alfalfa.

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 Tositumomab 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. Tositumomab)
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 Tositumomab

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 Tositumomab, 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 Tositumomab

This page covers Alfalfa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tositumomab 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.

Open the Tositumomab 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 Tositumomab 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 Tositumomab 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 Tositumomab
Steady interest

#2,683 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
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 Tositumomab, 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 Tositumomab supplement interactions › Every supplement checked against Tositumomab, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Alfalfa and Tositumomab Together: Common Questions

Can you take Alfalfa with Tositumomab?
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 Tositumomab 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 Tositumomab and Alfalfa?

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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.