Drug & supplement interaction

Tung Seed + Doxycycline

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

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 Tung Seed 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

Tung Seed 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 Tung Seed 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 Tung Seed 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.

Tung Seed safety at a glance

Tung Seed overall Avoid Tung seeds and oil are poisonous if eaten and are not safe as a supplement.
Pregnancy Likely Unsafe When used orally; avoid using. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally; avoid using. 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 Doxycycline and Tung Seed? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Tung Seed 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.

  • Stomach pain / Diarrhea / Vomiting Additional detail

    Tung Seed

    “Orally, candlenut can cause severe abdominal pain, violent vomiting, and diarrhea (6,4502,106671,111341).”

    Tung Seed · Natural Medicines adverse-effect record, reported in diarrhea.

    4 sources cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    2. 4502. Duke JA. CRC handbook of medicinal herbs. 1st ed. Boca Raton, FL: CRC Press, LLC, 1985.
    3. 106671. O'Brien DR, Szymczuk V, Albaro CA. Weight loss supplement causing acute heart block in a child. Cardiol Young 2020;30(1):131-133. PubMed
    4. 111341. Lawani O, Winter M. Heart Block Initiated by Candlenut Ingestion. Case Rep Cardiol 2022;2022:3679968. PubMed

    “A 16-year-old patient presented with acute onset abdominal pain, chest pain, and profuse and persistent vomiting following ingestion of both a tea made from boiling a whole candlenut and the boiled candlenut itself. The patient was also found to have first-degree heart block that later progressed to Mobitz type I second degree heart block with occasional 2:1 block, requiring ICU admission and monitoring.”

    Tung Seed · Natural Medicines adverse-effect record, reported in diarrhea.

    3 sources cited
    1. 106671. O'Brien DR, Szymczuk V, Albaro CA. Weight loss supplement causing acute heart block in a child. Cardiol Young 2020;30(1):131-133. PubMed
    2. 111341. Lawani O, Winter M. Heart Block Initiated by Candlenut Ingestion. Case Rep Cardiol 2022;2022:3679968. PubMed
    3. 111343. Koons AL, Laubach LT, Katz KD, Beauchamp GA. Mobitz Type II Atrioventricular Heart Block After Candlenut Ingestion. J Am Osteopath Assoc. 2020;120(12):839-843. PubMed

    Doxycycline

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

  • A skin rash Additional detail

    Tung Seed

    “Topically, candlenut can cause acute dermatitis.”

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

    1 source cited
    1. 4502. Duke JA. CRC handbook of medicinal herbs. 1st ed. Boca Raton, FL: CRC Press, LLC, 1985.

    Doxycycline

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

  • Nausea Additional detail

    Tung Seed

    Recorded for Tung Seed in the same Natural Medicines adverse-effect record shown under Stomach pain / Diarrhea / Vomiting above.

    Doxycycline

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

Reported for Tung Seed but not commonly for Doxycycline: confusion, a slow heartbeat, shortness of breath and chest pain.

Effects for Doxycycline come from the ADVERSE REACTIONS section of its FDA label; effects for Tung Seed 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.

Special populations

Tung Seed in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally; 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

How to take them

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

At least one FDA label for a product containing Doxycycline says to take it on an empty stomach. Most supplements — Tung Seed 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 Tung Seed 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 Tung Seed 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 Tung Seed 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 Tung Seed 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 Tung Seed 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 Tung Seed
Steady interest

#1,294 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Doxycycline
Top 5%

#41 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 Tung Seed reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Tung Seed 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 Tung Seed

What is Tung Seed?

  • Wood finishing and varnish (industrial)
  • Traditional folk skin applications
  • Traditional laxative use (historical)
  • Traditional topical remedies

Tung seed comes from the tung tree (Vernicia fordii), and its main product is tung oil, which is used mostly as an industrial wood finish, not as a food or medicine. The raw seeds and oil are toxic if swallowed and there is no reliable evidence supporting any health benefit. We do not recommend taking tung seed as a supplement.

Vernicia fordii · Euphorbiaceae · Seeds and the oil pressed from them (tung oil) · Tung oil (industrial), rarely available as a dietary supplement

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

Tung Seed: dosing

There is no established or safe dose of tung seed for use in people. Because the seeds and oil are toxic, no medical dosing exists, and we do not recommend taking it in any amount.If you see a product that claims to contain tung seed for health purposes, do not use it without first checking with a pharmacist or doctor. In general, tung oil should be treated as an industrial product only.

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

Read the full Tung Seed 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 belongs to the tetracycline family of antibiotics. It's prescribed for many types of bacterial infections, including respiratory tract infections, sexually transmitted infections (STIs), tick-borne illnesses like Rocky Mountain spotted fever, and eye infections. It's also used to help prevent malaria and, in some cases, as a helper treatment for severe acne.

In situations where penicillin-type antibiotics can't be used — due to allergy, for example — doxycycline can step in as an alternative. It should only be used for infections that are proven or strongly suspected to be caused by bacteria.

See full Doxycycline drug information
Keep checking

Other Drugs & Tung Seed

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

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

Tung Seed References

The 5 references that drive our Tung Seed 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. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Duke JA. CRC handbook of medicinal herbs. 1st ed. Boca Raton, FL: CRC Press, LLC, 1985.
  3. O'Brien DR, Szymczuk V, Albaro CA. Weight loss supplement causing acute heart block in a child. Cardiol Young 2020;30(1):131-133. PubMed
  4. Lawani O, Winter M. Heart Block Initiated by Candlenut Ingestion. Case Rep Cardiol 2022;2022:3679968. PubMed
  5. Koons AL, Laubach LT, Katz KD, Beauchamp GA. Mobitz Type II Atrioventricular Heart Block After Candlenut Ingestion. J Am Osteopath Assoc. 2020;120(12):839-843. 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 Tung Seed and Doxycycline Together: Common Questions

Is it safe to take Tung Seed with Doxycycline?
We do not list a known interaction between Tung Seed 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 Tung Seed and Doxycycline have any of the same side effects?
Yes — our sources link each of them separately to 5 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 Tung Seed 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 Tung Seed 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 — Tung Seed 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

Tung Seed 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Doxycycline and Tung Seed?

Our pharmacists answer your medication & supplement questions — free.

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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.