Drug & supplement interaction

Pyrethrum + Doxycycline

Doxycycline brand names: Vibra-Tabs, Vibramycin, Doryx, Monodox, Doxycin, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Pyrethrum and Doxycycline 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 label for Doxycycline states a food rule worth keeping to, and 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

Pyrethrum and Doxycycline

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 Doxycycline and Pyrethrum 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 Pyrethrum at all — not against Doxycycline, 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.

Pyrethrum safety at a glance

Pyrethrum overall Use caution Pyrethrum is an insecticide, not a dietary supplement, and should not be taken internally.
Pregnancy Avoid Avoid internal use and limit exposure to insecticide products during pregnancy due to lack of safety data.
Breastfeeding Avoid Avoid internal use while breastfeeding because safety has not been established.

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

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

No Interaction Found — But Data Suggests Pyrethrum and Doxycycline 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. One of them is worth acting on rather than waiting out — marked below.

  • An allergic reaction Worth acting on Additional detail

    Pyrethrum

    “Pyrethrum has limited toxicity. The symptoms of overdose include headache, tinnitus, nausea, tingling of fingers and toes, respiratory disturbances, and other symptoms of neurotoxicity (18). The pyrethrum flower or derivatives of it might cause an allergic reaction in individuals sensitive to the Asteraceae/Compositae family.”

    Pyrethrum · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Doxycycline

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

  • Headache / Nausea Additional detail

    Pyrethrum

    Recorded for Pyrethrum in the same Natural Medicines adverse-effect record shown under An allergic reaction above.

    Doxycycline

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

Reported for Pyrethrum but not commonly for Doxycycline: numbness or tingling and ringing in the ears.

Effects for Doxycycline come from the ADVERSE REACTIONS section of its FDA label; effects for Pyrethrum come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Doxycycline Products Have a Food Rule — Pyrethrum Should Not Break It

At least one FDA label for a product containing Doxycycline says to take it on an empty stomach. Most supplements — Pyrethrum included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Doxycycline on its own and move Pyrethrum to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Doxycycline products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

2 DOSAGE AND ADMINISTRATION Take one Doxycycline capsule (40 mg) once daily in the morning on an empty stomach, preferably at least one hour prior to or two hours after meals.

From the Dosage and Administration section of the FDA label we read for Doxycycline — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Pyrethrum or Doxycycline

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

This page covers Pyrethrum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Doxycycline page lists 166 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Oleander (major) and Siberian Cocklebur (major).

By severity: 7 major · 139 moderate · 20 minor.

From our pharmacist’s overview on the Doxycycline page

“St. John's wort is the supplement I would flag first for anyone on doxycycline (Vibramycin, Doryx), because it can speed the antibiotic out of the body and leave an infection undertreated.”

Reviewed by 2 · Jul 18, 2026

Open the Doxycycline interaction page

How much people look this up

Where Pyrethrum and Doxycycline 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 Pyrethrum
Top half

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

29 days ago today
Medication Doxycycline
Top 5%

#71 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 Pyrethrum reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Pyrethrum and Doxycycline 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 Pyrethrum

What is Pyrethrum?

  • Natural insect repellent
  • Killing fleas, lice, and other pests
  • Garden and household insecticide
  • Traditional use against parasites

Pyrethrum is a daisy-like flower whose extracts (called pyrethrins) are widely used as a natural insecticide for plants, pets, and lice. It is not a supplement meant to be taken by mouth, and there is no good evidence supporting any internal health use. If you use pyrethrum products, treat them as pesticides and follow label directions carefully.

Tanacetum cinerariifolium · Asteraceae · Dried flower heads · Insecticide powders, sprays, and extracts (pyrethrins); rarely used internally

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

Pyrethrum: dosing

There is no established or recommended internal dose for pyrethrum, and it should not be taken as a supplement. For insecticide, lice, or flea products, the correct amount depends entirely on the specific product.Always follow the directions on the product label exactly, and do not use more or more often than directed.

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

Read the full Pyrethrum monograph & all interactions
Medication

About Doxycycline

What Is Doxycycline Used For?

Brand names: Vibra-Tabs, Vibramycin, Doryx, Monodox, Doxycin, Doxy, Doxylin, Doxy-D, Periostat, Doxycycline Injection, Oracea, Xyrosa

Doxycycline is an antibiotic. It treats infections caused by bacteria, and it does not work on viruses.

Several products carry a broad list of uses, including rickettsial infections, sexually transmitted infections, respiratory tract infections, eye infections, and anthrax after exposure. Some product labels also list malaria prevention, and use as an add-on treatment for acute intestinal amebiasis and severe acne. Doxycycline for Injection (Doxy 100, intravenous) is approved for infections caused by a listed set of microorganisms. Doxycycline capsules in the Oracea-type low-dose form are described in the evidence for inflammatory lesions of rosacea.

See full Doxycycline drug information
Keep checking

Other Drugs & Pyrethrum

Browse every other medication we’ve checked against Pyrethrum — 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 Pyrethrum 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 Pyrethrum list.

See the full Pyrethrum interactions page
See every supplement checked against Doxycycline, ranked by severity
Evidence & sources

Pyrethrum References

The 3 references that drive our Pyrethrum 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  2. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  3. Drugs in Pregnancy and Lactation. 4th ed. Baltimore, MD: Williams & Wilkins, 1994.

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 Pyrethrum and Doxycycline Together: Common Questions

Is it safe to take Pyrethrum with Doxycycline?
We do not list a known interaction between Pyrethrum and Doxycycline. 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 Pyrethrum and Doxycycline 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.
Should I take Pyrethrum and Doxycycline at the same time of day?
At least one FDA label for a product containing Doxycycline says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Doxycycline on its own and move Pyrethrum to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
Does Doxycycline interact with any supplements?
Yes. Doxycycline has documented interactions with 166 supplements in our database — Pyrethrum is not one of them. The Doxycycline 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

Pyrethrum monograph Uses, safety profile, and every drug interaction in one place Doxycycline drug information The full plain-English guide to this medication Doxycycline supplement interactions Every supplement checked against Doxycycline, 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Doxycycline and Pyrethrum?

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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.