Drug & supplement interaction

Peru Balsam + Famciclovir

Famciclovir brand name: Famvir.

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 Peru Balsam and Famciclovir 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

Peru Balsam and Famciclovir

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 Famciclovir and Peru Balsam 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 Peru Balsam at all — not against Famciclovir, 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.

Peru Balsam safety at a glance

Peru Balsam overall Use caution Generally used topically but is a common cause of allergic and contact skin reactions.
Pregnancy Likely Unsafe When used orally in medicinal amounts; avoid using. There is insufficient reliable information available about the safety of Peru balsam when used topically; av... Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used topically because systemic toxicity to babies can occur following application of Peru balsam to the nipples of nursing mothers. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Famciclovir and Peru Balsam? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Peru Balsam and Famciclovir May Share Several of the Same Side Effects

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. 2 of them are worth acting on rather than waiting out — marked below.

  • Kidney problems Worth acting on Additional detail

    Peru Balsam

    “Peru balsam can cause kidney damage when taken orally or applied topically in large amounts (18). Topical use is associated with allergic contact dermatitis and other skin reactions (2,18).”

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

    2 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.

    Famciclovir

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

  • Hives Worth acting on Additional detail

    Peru Balsam

    “There are numerous reports of Peru balsam and its extracts causing allergic contact dermatitis, particularly when present in fragrances, cosmetics, and topical medicines. Among people who undergo patch testing for allergic contact dermatitis, reactions to Peru balsam occur in 4% to 8.4%, of whom 70% are women.”

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

    4 sources cited
    1. 100650. Turic P, Lipozencic J, Milavec-Puretic V, Kulisic SM. Contact allergy caused by fragrance mix and Myroxylon pereirae (balsam of Peru) - a retrospective study. Coll Antropol 2011;35(1):83-7.
    2. 100908. Thyssen JP, Carlsen BC, Menné T, Johansen JD. Trends of contact allergy to fragrance mix I and Myroxylon pereirae among Danish eczema patients tested between 1985 and 2007. Contact Dermatitis 2008;59(4):238-44. doi: 10.1111/j.1600-0536.2008.01418.x.
    3. 100909. Avalos-Peralta P, García-Bravo B, Camacho FM. Sensitivity to Myroxylon pereirae resin (balsam of Peru). A study of 50 cases. Contact Dermatitis 2005;52(6):304-6.
    4. 100907. Tan S, Tam MM, Nixon RL. Allergic contact dermatitis to Myroxylon pereirae (Balsam of Peru) in papaw ointment causing cheilitis. Australas J Dermatol 2011;52(3):222-3. doi: 10.1111/j.1440-0960.2011.00772.x. PubMed

    Famciclovir

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

  • A skin rash reported in 4.1% of FDA reports for Famciclovir Additional detail

    Peru Balsam

    Recorded for Peru Balsam in the same Natural Medicines adverse-effect record shown under Kidney problems above.

    Famciclovir

    Listed in the ADVERSE REACTIONS section of the FDA label for Famciclovir, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Effects for Famciclovir come from the ADVERSE REACTIONS section of its FDA label; effects for Peru Balsam come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 2,753 voluntary FDA FAERS reports for Famciclovir 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.

Special populations

Peru Balsam in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally in medicinal amounts; avoid using. There is insufficient reliable information available about the safety of Peru balsam when used topically; avoid using.

Lactation Possibly Unsafe

When used topically because systemic toxicity to babies can occur following application of Peru balsam to the nipples of nursing mothers.

Lactation Likely Unsafe

When used orally in medicinal amounts; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Peru Balsam or Famciclovir

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

This page covers Peru Balsam only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Famciclovir page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Famciclovir page

“Famciclovir (Famvir) treats herpes infections like shingles and cold sores, and it only works if enough of the drug gets absorbed from your gut, which is exactly where every supplement on this list can interfere. The entry I would take most seriously is activated charcoal, the lone major-rated interaction, because charcoal binds medica…”

Reviewed by 2 · Jul 18, 2026

Open the Famciclovir interaction page

How much people look this up

Where Peru Balsam and Famciclovir 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 Peru Balsam
Steady interest

#1,415 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Famciclovir
Top half

#1,395 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 Peru Balsam reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Peru Balsam and Famciclovir records this page draws on were last updated July 11, 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 Peru Balsam

What is Peru Balsam?

  • Wound and skin healing
  • Hemorrhoids
  • Coughs and sore throat
  • Antimicrobial and antiseptic
  • Diaper rash and minor skin irritation

Peru Balsam is a fragrant tree resin used mainly in topical products for wounds, hemorrhoids, and skin care, and sometimes in cough and throat remedies. Evidence for most uses is limited and largely traditional, and it is a well-known cause of allergic skin reactions, so use it cautiously and check with your pharmacist or doctor first.

Myroxylon balsamum var. pereirae · Fabaceae · Balsam (resin) obtained from the tree bark · Topical ointments, creams, suppositories, lozenges, and as a fragrance ingredient

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

Peru Balsam: dosing

There is no well-established standardized dose for Peru Balsam. It is usually found as one ingredient in finished topical products, lozenges, or syrups rather than as a stand-alone supplement.Follow the directions on the specific product label, and use the smallest amount needed.

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

Read the full Peru Balsam monograph & all interactions
Medication

About Famciclovir

What Is Famciclovir Used For?

Brand name: Famvir

Famciclovir tablets are used in adults to treat recurrent cold sores (herpes labialis), recurrent episodes of genital herpes, and shingles (herpes zoster). For genital herpes, it can also be taken daily as suppressive therapy to reduce how often outbreaks happen.

In adults living with HIV, famciclovir is used to treat recurrent episodes of orolabial herpes (cold sores) or genital herpes. It is not approved for a first-ever genital herpes outbreak, herpes affecting the eye (ophthalmic zoster), or for use in children.

Most-Reported Side Effects for Famciclovir

From FAERS, the FDA’s public side-effect reporting system (2,753 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 191 reports
Diarrhea 183 reports
Nausea 153 reports
Headache 142 reports
Rash 114 reports
See full Famciclovir drug information
Keep checking

Other Drugs & Peru Balsam

Browse every other medication we’ve checked against Peru Balsam — 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
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Peru Balsam list.

See the full Peru Balsam interactions page
See every supplement checked against Famciclovir, ranked by severity
Evidence & sources

Peru Balsam References

The 7 references that drive our Peru Balsam 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. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  3. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  4. Turic P, Lipozencic J, Milavec-Puretic V, Kulisic SM. Contact allergy caused by fragrance mix and Myroxylon pereirae (balsam of Peru) - a retrospective study. Coll Antropol 2011;35(1):83-7.
  5. Tan S, Tam MM, Nixon RL. Allergic contact dermatitis to Myroxylon pereirae (Balsam of Peru) in papaw ointment causing cheilitis. Australas J Dermatol 2011;52(3):222-3. doi: 10.1111/j.1440-0960.2011.00772.x. PubMed
  6. Thyssen JP, Carlsen BC, Menné T, Johansen JD. Trends of contact allergy to fragrance mix I and Myroxylon pereirae among Danish eczema patients tested between 1985 and 2007. Contact Dermatitis 2008;59(4):238-44. doi: 10.1111/j.1600-0536.2008.01418.x.
  7. Avalos-Peralta P, García-Bravo B, Camacho FM. Sensitivity to Myroxylon pereirae resin (balsam of Peru). A study of 50 cases. Contact Dermatitis 2005;52(6):304-6.

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 Peru Balsam and Famciclovir Together: Common Questions

Is it safe to take Peru Balsam with Famciclovir?
We do not list a known interaction between Peru Balsam and Famciclovir. 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 Peru Balsam and Famciclovir have any of the same side effects?
Yes — our sources link each of them separately to 3 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.
Does Famciclovir interact with any supplements?
Yes. Famciclovir has documented interactions with 17 supplements in our database — Peru Balsam is not one of them. The Famciclovir 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

Peru Balsam monograph Uses, safety profile, and every drug interaction in one place Famciclovir drug information The full plain-English guide to this medication Famciclovir supplement interactions Every supplement checked against Famciclovir, 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 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Famciclovir and Peru Balsam?

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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.