Drug & supplement interaction

Castoreum + Interferon Alfa-2b

Interferon Alfa-2b brand names: Rebetron, Intron A, Viraferon.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Castoreum and Interferon Alfa-2b 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

Castoreum and Interferon Alfa-2b

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 Alfa-2b and Castoreum 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Castoreum at all — not against Interferon Alfa-2b, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Castoreum safety at a glance

Castoreum overall Not established Modern safety data for medicinal use is essentially lacking, so caution is warranted.
Pregnancy Avoid There is no safety data; avoid medicinal use during pregnancy.
Breastfeeding Avoid There is no safety data; avoid medicinal use while breastfeeding.

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

Still wondering about combining Interferon Alfa-2b and Castoreum? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
Everything else you take

See Every Supplement That Interacts With Interferon Alfa-2b

This page covers Castoreum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Interferon Alfa-2b 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 Alfa-2b page

“People taking interferon alfa-2b (Intron A, Rebetron) are usually treating hepatitis or a cancer, so the liver may already be under strain, and that is exactly where most of this list points. Of the 57 supplements on file, 38 can add to liver stress, and all three major-rated interactions sit in that group: Siberian cocklebur, which ha…”

Reviewed by 2 · Jul 18, 2026

Open the Interferon Alfa-2b interaction page

How much people look this up

Where Castoreum and Interferon Alfa-2b 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 Castoreum
Steady interest

#1,091 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Interferon Alfa-2b
Steady interest

#1,898 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. Castoreum is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Castoreum reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Castoreum and Interferon Alfa-2b records this page draws on were last updated June 22, 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 Castoreum

What is Castoreum?

  • Traditional remedy for menstrual or 'hysteria' complaints
  • Folk use for headache and pain
  • Flavoring agent (vanilla-like notes)
  • Fragrance and perfume ingredient
  • Historical use as a sedative or antispasmodic

Castoreum is a brownish, strong-smelling substance taken from the castor sacs of beavers, not a plant. It has a long history in perfumes, flavorings, and folk medicine, but there is no reliable modern evidence that it treats any health condition, so it should not be relied on as a medicine.

Castor sac secretion (castoreum) from beavers, sometimes combined with castor gland and surrounding tissue · Tincture (in traditional and homeopathic medicine), perfume and fragrance ingredient, food flavoring extract

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

Castoreum: dosing

There is no established or standardized medicinal dose for castoreum. It is not a recognized medicine, and reliable dosing guidelines do not exist.If you encounter a product that contains castoreum (for example, a traditional tincture or homeopathic preparation), follow the directions on the label and do not exceed them.

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

Read the full Castoreum monograph & all interactions
Medication

About Interferon Alfa-2b Injection

What Is Interferon Alfa-2b Injection Used For?

Brand names: Rebetron, Intron A, Viraferon

  • Interferon alfa-2b injection is used to treat a number of conditions.

  • Interferon alfa-2b injection is used

    • alone or in combination with ribavirin (Copegus, Rebetol, Ribasphere) to treat chronic (long-term) hepatitis C infection (swelling of the liver caused by a virus) in people who show signs of liver damage,

    • to treat chronic hepatitis B infection (swelling of the liver caused by a virus) in people who show signs of liver damage,

    • to treat hairy cell leukemia (a white blood cell cancer),

    • to treat genital warts,

    • to treat Kaposi's sarcoma (a type of cancer that causes abnormal tissue to grow on different parts of the body) related to acquired immunodeficiency syndrome (AIDS),

    • to treat malignant melanoma (a cancer that begins in certain skin cells) in certain people who have had surgery to remove the cancer,

    • along with another medication to treat follicular non-Hodgkin's lymphoma (NHL; a slow-growing blood cancer).

  • Interferon alfa-2b is in a class of medications called immunomodulators. Interferon alfa-2b works to treat hepatitis C virus (HCV) and hepatitis B virus (HBV) by decreasing the amount virus in the body. Interferon alfa-2b may not cure hepatitis B or hepatitis C or prevent you from developing complications from these infections such as cirrhosis (scarring) of the liver, liver failure, or liver cancer. It also may not prevent the spread of hepatitis B or C to other people. It is not known exactly how interferon alfa-2b works to treat cancer or genital warts.

See full Interferon Alfa-2b Injection drug information
Keep checking

Other Drugs & Castoreum

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

0Major
0Moderate
0Minor
2,829No known interaction
No interaction 2,829 drugs checked — show the list
Evidence & sources

Castoreum References

The 3 sources that drive our Castoreum monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. Castoreum is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

  1. Castoreum (chemical information) — PubChem (NIH National Library of Medicine) Source
  2. Dietary Supplements: What You Need to Know — NIH Office of Dietary Supplements Source
  3. Herbal Medicine — MedlinePlus (NIH National Library of Medicine) Source

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 Castoreum and Interferon Alfa-2b Together: Common Questions

Is it safe to take Castoreum with Interferon Alfa-2b?
We do not list a known interaction between Castoreum and Interferon Alfa-2b. 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.
Does Interferon Alfa-2b interact with any supplements?
Yes. Interferon Alfa-2b has documented interactions with 57 supplements in our database — Castoreum is not one of them. The Interferon Alfa-2b interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Interferon Alfa-2b and Castoreum?

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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.