Drug & supplement interaction

Horsetail + Interferon Beta-1a

Interferon Beta-1a brand names: Rebif, Avonex.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Horsetail and Interferon Beta-1a 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.

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Interaction report

Horsetail and Interferon Beta-1a

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 Interferon Beta-1a and Horsetail 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.

Horsetail safety at a glance

Horsetail overall Use caution May be used short-term by healthy adults, but long-term use and unverified products carry real risks.
Pregnancy Avoid Not enough safety data; avoid use during pregnancy.
Breastfeeding Avoid Not enough safety data; avoid while breastfeeding.

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

Still wondering about combining Interferon Beta-1a and Horsetail? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Interferon Beta-1a

Interactions in our licensed database are recorded against drug classes, not just single drug names. Interferon Beta-1a is filed under 2 classifications — photosensitizing drugs, hepatotoxic drugs. Horsetail has documented interactions with 5 drug classes — the most serious being antidiabetes drugs (moderate), diuretic drugs (moderate) and efavirenz (sustiva) (moderate) — and none of Interferon Beta-1a’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

Horsetail Does Interact With Other Medications

Horsetail has 188 moderate known drug interactions in our database — Interferon Beta-1a isn’t one of them. If you take anything else, check it against the full list below.

Moderate 188 No known interaction 2,642 (incl. Interferon Beta-1a)
Taking anything else?

Check Another of Your Medications Against Horsetail

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

What to actually watch for

What Horsetail Itself Has Been Linked To

This is not an interaction — nothing below involves Interferon Beta-1a. It is the side-effect record for Horsetail on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Horsetail, this list is the first place to look. 3 entries are worth acting on rather than waiting out — marked below.

  • Low sodium Worth acting on Additional detail

    “There are at least 4 case reports of hyponatremia thought to be at least partially associated with horsetail consumption. In one case report, an elderly patient who had taken oral horsetail 15 mg daily for 10 years presented with hyponatremia and syndrome of inappropriate secretion of antidiuretic hormone (SIADH) secondary to reduced oral intake and nausea for the previous 2 days.”

    Horsetail · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    1 source cited
    1. 108851. Bates D, Duong TB, Kheyson S, Moore K. Hyponatremia Secondary to Decreased Oral Intake and SIADH and Possibly Exacerbated by Horsetail (Equisetum arvense). Can J Hosp Pharm 2021;74(4):386-389. PubMed
  • Pancreatitis / Raised blood pressure Worth acting on Additional detail

    “Orally, horsetail has been associated with mild gastrointestinal side effects including abdominal distension, increased frequency of bowel movements, and nausea. Orally, chronic consumption of horsetail infusion has been associated with acute pancreatitis.”

    Horsetail · Natural Medicines adverse-effect record, reported in dyslipidemia.

    2 sources cited
    1. 55576. Tiktinskii, O. L. and Bablumian, I. A. [Therapeutic action of Java tea and field horsetail in uric acid diathesis]. Urol.Nefrol.(Mosk) 1983;3(1):47-50.
    2. 97574. García Gavilán MD, Moreno García AM, Rosales Zabal JM, Navarro Jarabo JM, Sánchez Cantos A. Case of drug-induced acute pancreatitis produced by horsetail infusions. Rev Esp Enferm Dig. 2017 Apr;109(4):301-304. PubMed
  • Liver problems Worth acting on Additional detail

    “In one case report, a patient with asymptomatic hepatitis B developed symptomatic liver failure following consumption of boiled horsetail juice 500 mL daily for 2 weeks. Liver enzymes returned to normal following discontinuation of the juice. It is not known if the horsetail juice was contaminated or mixed with other ingredients.”

    Horsetail · Natural Medicines adverse-effect record, reported in hepatitis.

    1 source cited
    1. 92291. Klnçalp S, Ekiz F, Basar Ö, Coban S, Yüksel O. Equisetum arvense (Field Horsetail)-induced liver injury. Eur J Gastroenterol Hepatol. 2012 Feb;24(2):213-4. PubMed
  • Bloating or gas / Nausea Additional detail

    “There is limited clinical research evaluating the safety of horsetail.

    Most Common Adverse Effects:

    Orally: Abdominal distension, increased bowel movements, and nausea.”

    Horsetail · Natural Medicines adverse-effect record, reported in nausea and vomiting.

  • Diarrhea Additional detail

    Recorded for Horsetail in the same Natural Medicines adverse-effect record shown under Bloating or gas / Nausea above.

  • A skin rash Additional detail

    “In one case report, a patient developed seborrheic dermatitis after topical application of horsetail, requiring treatment with local epinephrine and oral antihistamines. The nicotine component of horsetail was determined to be the likely cause of this reaction.”

    Horsetail · Natural Medicines adverse-effect record, reported in dermatitis.

    1 source cited
    1. 13563. Sudan BJ. Seborrhoeic dermatitis induced by nicotine of horsetails (Equisetum arvense L.). Contact Dermatitis 1985;13:201-2.

Everything above comes from the Natural Medicines adverse-effect record for Horsetail — expand a row for the licensed statement it rests on. We haven’t matched Interferon Beta-1a to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Interferon Beta-1a.

From our Q&A

Questions About Horsetail or Interferon Beta-1a

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Horsetail or Interferon Beta-1a, 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 Interferon Beta-1a

This page covers Horsetail only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Interferon Beta-1a page lists 57 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Beer (major), Siberian Cocklebur (major), Wine (major), Alfalfa (moderate) and Angelica Archangelica (moderate).

By severity: 3 major · 53 moderate · 1 minor.

From our pharmacist’s overview on the Interferon Beta-1a page

“Siberian cocklebur, an herb tied to documented cases of liver failure, is the first name to know for anyone injecting interferon beta-1a (Rebif, Avonex) for multiple sclerosis. Interferon beta-1a can strain the liver on its own, which is why prescribers order routine liver blood tests, and 38 of the 57 supplements on file carry that sa…”

Reviewed by 2 · Jul 18, 2026

Open the Interferon Beta-1a interaction page

One more smart check

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

We hold 2,089 real supplement products containing Horsetail, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Horsetail. Even though Horsetail itself has no known interaction with Interferon Beta-1a, 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 Horsetail and Interferon Beta-1a 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 Horsetail
Top 10%

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

29 days ago today
Medication Interferon Beta-1a
Steady interest

#1,920 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 Horsetail reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Horsetail and Interferon Beta-1a 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 Horsetail

What is Horsetail?

Horsetail
  • Fluid retention (mild diuretic)
  • Urinary and bladder concerns
  • Hair, skin, and nail support
  • Wound healing
  • Bone health

Horsetail is a traditional herb most often used as a mild diuretic and for hair, nail, and bone support, but high-quality human evidence is limited. It can cause thiamine (vitamin B1) loss with long-term use, and some related species are toxic, so choose products carefully and talk to your pharmacist or doctor before using it.

Equisetum arvense · Equisetaceae · Aerial parts (stems) · Tea, capsules, tablets, liquid extract, tincture, dried herb

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

Horsetail: dosing

There is no well-established standardized dose for horsetail. The right amount can vary by product, form (tea, capsule, or extract), and how it is prepared.The safest approach is to follow the directions on the product label and not exceed them.

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

Read the full Horsetail monograph & all interactions
Medication

About Interferon Beta-1a Intramuscular Injection

What Is Interferon Beta-1a Intramuscular Injection Used For?

Brand names: Rebif, Avonex

  • Interferon beta-1a intramuscular injection is used to treat adults with various forms of multiple sclerosis (MS; a disease in which the nerves do not function properly and people may experience weakness, numbness, loss of muscle coordination, and problems with vision, speech, and bladder control) including:

    • clinically isolated syndrome (CIS; nerve symptom episodes that last at least 24 hours),

    • relapsing-remitting forms (course of disease where symptoms flare up from time to time), or

    • secondary progressive forms (course of disease where relapses occur more often).

  • Interferon beta-1a is in a class of medications called immunomodulators. It works by decreasing inflammation and preventing nerve damage that may cause symptoms of multiple sclerosis.

Most-Reported Side Effects for Interferon Beta-1a

From FAERS, the FDA’s public side-effect reporting system (192,069 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Multiple sclerosis relapse 15,851 reports
Influenza like illness 13,253 reports
Fatigue 11,554 reports
Fall 10,604 reports
Multiple sclerosis 9,358 reports
See full Interferon Beta-1a Intramuscular Injection drug information
Keep checking

Other Drugs & Horsetail

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

0Major
188Moderate
0Minor
2,641No known interaction
188 Moderate 2,641 No interaction
Moderate

188 interactions

Showing 60 of 188 moderate interactions — see all 188 on the Horsetail page.

No interaction 2,641 drugs checked — show the list

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

Showing the 60 most looked-up of 2,641 medications checked with no known interaction — see the full Horsetail list.

See the full Horsetail interactions page
See every supplement checked against Interferon Beta-1a, ranked by severity
Evidence & sources

Horsetail References

The 14 references that drive our Horsetail 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. Sudan BJ. Seborrhoeic dermatitis induced by nicotine of horsetails (Equisetum arvense L.). Contact Dermatitis 1985;13:201-2.
  2. Perez Gutierrez RM, Laguna GY, Walkowski A. Diuretic activity of Mexican equisetum. J Ethnopharmacol 1985;14:269-72. PubMed
  3. Lemus I, Garcia R, Erazo S, et al. Diuretic activity of an Equisetum bogotense tea (Platero herb): evaluation in healthy volunteers. J Ethnopharmacol 1996;54:55-8. PubMed
  4. Revilla MC, Andrade-Cetto A, Islas S, Wiedenfeld H. Hypoglycemic effect of Equisetum myriochaetum aerial parts on type 2 diabetic patients. J Ethnopharmacol 2002;81:117-20. PubMed
  5. Tiktinskii, O. L. and Bablumian, I. A. [Therapeutic action of Java tea and field horsetail in uric acid diathesis]. Urol.Nefrol.(Mosk) 1983;3(1):47-50.
  6. Henderson JA, Evans EV, and McIntosh RA. The antithiamine action of Equisetum. J Amer Vet Med Assoc 1952;120:375-378.
  7. Carneiro DM, Freire RC, Honório TC, Zoghaib I, Cardoso FF, Tresvenzol LM, de Paula JR, Sousa AL, Jardim PC, da Cunha LC. Randomized, Double-Blind Clinical Trial to Assess the Acute Diuretic Effect of Equisetum arvense (Field Horsetail) in Healthy Voluntee
  8. Klnçalp S, Ekiz F, Basar Ö, Coban S, Yüksel O. Equisetum arvense (Field Horsetail)-induced liver injury. Eur J Gastroenterol Hepatol. 2012 Feb;24(2):213-4. PubMed
  9. Ortega García JA, Angulo MG, Sobrino-Najul EJ, Soldin OP, Mira AP, Martínez-Salcedo E, Claudio L. Prenatal exposure of a girl with autism spectrum disorder to 'horsetail' (Equisetum arvense) herbal remedy and alcohol: a case report. J Med Case Rep. 2011 M PubMed
  10. Cordova E, Morganti L, Rodriguez C. Possible Drug-Herb Interaction between Herbal Supplement Containing Horsetail (Equisetum arvense) and Antiretroviral Drugs. J Int Assoc Provid AIDS Care. 2017;16(1):11-13.
  11. García Gavilán MD, Moreno García AM, Rosales Zabal JM, Navarro Jarabo JM, Sánchez Cantos A. Case of drug-induced acute pancreatitis produced by horsetail infusions. Rev Esp Enferm Dig. 2017 Apr;109(4):301-304. PubMed
  12. Vieira GT, de Oliveira TT, Carneiro MAA, et al. Antidiabetic effect of Equisetum giganteum L. extract on alloxan-diabetic rabbit. J Ethnopharmacol. 2020;260:112898. PubMed
  13. Health Canada. Organism-Equisetum arvense. Available at: http://webprod.hc-sc.gc.ca/nhpid-bdipsn/ingredReq.do?id=6117&lang=eng. Accessed 21-July 2021.
  14. Bates D, Duong TB, Kheyson S, Moore K. Hyponatremia Secondary to Decreased Oral Intake and SIADH and Possibly Exacerbated by Horsetail (Equisetum arvense). Can J Hosp Pharm 2021;74(4):386-389. 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 Horsetail and Interferon Beta-1a Together: Common Questions

Is it safe to take Horsetail with Interferon Beta-1a?
We do not list a known interaction between Horsetail and Interferon Beta-1a. 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.
How was the Horsetail and Interferon Beta-1a combination checked?
Interactions in our licensed database are recorded against drug classes. Interferon Beta-1a is filed under 2 classifications, and Horsetail has documented interactions with 5 drug classes — none of Interferon Beta-1a'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 Horsetail interact with any other medications?
Yes. Horsetail has 188 documented drug interactions in our database — Interferon Beta-1a 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 Interferon Beta-1a interact with any supplements?
Yes. Interferon Beta-1a has documented interactions with 57 supplements in our database — Horsetail is not one of them. The Interferon Beta-1a 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

Horsetail monograph Uses, safety profile, and every drug interaction in one place Interferon Beta-1a Intramuscular Injection drug information The full plain-English guide to this medication Interferon Beta-1a supplement interactions Every supplement checked against Interferon Beta-1a, 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 14 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Interferon Beta-1a and Horsetail?

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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.