Drug & supplement interaction

Oregano + Quinidine

Quinidine brand names: Quinaglute Duratabs, Quinaglute, Duraquin, Cardioquin, Cin-Quin, and others.

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 Oregano and Quinidine 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

Oregano and Quinidine

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 Quinidine and Oregano 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.

Oregano safety at a glance

Oregano overall Use caution Safe as a food, but concentrated oregano oil supplements are stronger and less studied.
Pregnancy Possibly Unsafe When used orally in medicinal amounts. Oregano is thought to have abortifacient and emmenagogue effects. Read the full pregnancy detail
Breastfeeding Use caution Stick to normal food amounts; safety of supplements while breastfeeding is not established.

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.

Pharmacist analysis

Oregano (and oregano oil) supplements are generally considered safe and there is no indication that there is an interaction between the drug highlighted in this interaction monograph and oregano.

However, as with all supplements, it is important to talk to your doctor before starting anything new, so you can be appropriately monitored.

In terms of drug interactions that have been reported with oregano, below are some examples.

Anticoagulant; Antiplatelet Drugs

Anticoagulants and antiplatelet drugs work by slowing down or preventing blood clotting. While they are essential medications for individuals with certain conditions, they come with an increased risk of bleeding.

Some studies have reported that oregano oil may also increase the risk of bleeding, as it contains compounds that have antithrombin activity and can inhibit platelet aggregation.

Therefore, taking oregano oil along with anticoagulants or antiplatelet drugs may increase the risk of bleeding, bruising, and other adverse effects.

Anti-Diabetic Drugs

Several studies suggest that oregano supplements may help lower blood glucose (i.e., sugar) levels. In vitro and animal research has shown that oregano extracts might stimulate glucose uptake and reduce blood glucose levels.

Therefore, based on the available evidence, combining oregano oil with antidiabetic drugs could potentially cause blood sugar levels to drop too low, leading to hypoglycemia.

However, it is important to note that studies reporting that oregano can reduce blood glucose levels have not reported it causing hypoglycemia.

References

  • Anti-hyperglycaemic activity of the aqueous extract of Origanum vulgare growing wild in Tafilalet region. PubMed
  • Inhibitory effect of clonal oregano extracts against porcine pancreatic amylase in vitro. PubMed
  • Antithrombin activity of some constituents from Origanum vulgare. PubMed
  • Comparative screening of plant essential oils: phenylpropanoid moiety as basic core for antiplatelet activity. PubMed

—

Still wondering about combining Quinidine and Oregano? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Quinidine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Quinidine is filed under 9 classifications — including cytochrome p450 2d6 (cyp2d6) inhibitors, qt interval-prolonging drugs, p-glycoprotein substrates. Oregano has documented interactions with 2 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate) and antidiabetes drugs (moderate) — and none of Quinidine’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

Oregano Does Interact With Other Medications

Oregano has 208 moderate known drug interactions in our database — Quinidine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 208 No known interaction 2,622 (incl. Quinidine)
Taking anything else?

Check Another of Your Medications Against Oregano

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

What to actually watch for

No Interaction Found — But Data Suggests Oregano and Quinidine 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.

  • A severe allergic reaction Worth acting on Additional detail

    Oregano

    “Orally, oregano is well tolerated when used in amounts typically found in foods. There is currently a limited amount of information available about the safety of oregano when used in larger amounts as medicine.

    Most Common Adverse Effects:

    Orally: Gastrointestinal upset.

    Topically: Dermatitis in sensitive individuals.

    Serious Adverse Effects (Rare):

    Orally: Systemic allergic reactions, including anaphylaxis, in sensi…”

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

    Quinidine

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

  • Low blood pressure / Itching Additional detail

    Oregano

    “Systemic allergic reactions have been reported with oregano. A 45-year-old male developed pruritus, respiratory difficulty, hypotension, swelling of the lips and tongue, and facial edema after ingesting pizza seasoned with oregano. He had 2 similar episodes after ingesting foods seasoned with thyme, another member of the Lamiaceae family.”

    Oregano · Natural Medicines adverse-effect record, reported in hypotension.

    1 source cited
    1. 3705. Benito M, Jorro G, Morales C, et al. Labiatae allergy: systemic reactions due to ingestion of oregano and thyme. Ann Allergy Asthma Immunol 1996;76:416-8. PubMed

    Quinidine

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

  • A skin rash Additional detail

    Oregano

    “Oregano has been reported to cause allergic contact dermatitis. Topically, oregano oil in concentrations of greater than 1% has been reported to cause irritation when applied to mucous membranes.”

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

    3 sources cited
    1. 46902. Futrell, J. M. and Rietschel, R. L. Spice allergy evaluated by results of patch tests. Cutis 1993;52(5):288-290.
    2. 67348. Ragi, J., Pappert, A., Rao, B., Havkin-Frenkel, D., and Milgraum, S. Oregano extract ointment for wound healing: a randomized, double-blind, petrolatum-controlled study evaluating efficacy. J.Drugs Dermatol. 2011;10(10):1168-1172.
    3. 88188. Singletary K. Oregano: overview of the literature on health benefits. Nutrition Today 2010;45(3):129-38.

    Quinidine

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

Reported for Oregano but not commonly for Quinidine: stomach upset, an allergic reaction and swelling.

Effects for Quinidine come from the ADVERSE REACTIONS section of its FDA label; effects for Oregano 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

Oregano in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally in medicinal amounts. Oregano is thought to have abortifacient and emmenagogue effects.

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 Oregano or Quinidine

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

This page covers Oregano only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Quinidine page lists 207 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 15 major · 157 moderate · 35 minor.

From our pharmacist’s overview on the Quinidine page

“Grapefruit belongs nowhere near quinidine. The juice blocks the main enzyme that clears this heart rhythm medicine, so quinidine levels can climb into dangerous territory, and it leads a list of 207 supplement and herbal ingredients I would treat with real seriousness, 15 of them rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Quinidine interaction page

One more smart check

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

We hold 1,632 real supplement products containing Oregano, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Oregano. Even though Oregano itself has no known interaction with Quinidine, 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 Oregano and Quinidine 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 Oregano
Top 10%

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

29 days ago today
Medication Quinidine
Steady interest

#1,844 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 Oregano reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Oregano and Quinidine 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 Oregano

What is Oregano?

Oregano
  • Digestive upset
  • Respiratory and cold symptoms
  • Antimicrobial support
  • Intestinal parasites
  • Skin and fungal concerns

Oregano is a common Mediterranean cooking herb that is also sold as a concentrated oil or supplement, often standardized for a compound called carvacrol. While lab studies suggest it may have antimicrobial and antioxidant properties, strong human evidence for treating any specific health condition is limited. Used as a food, oregano is very safe; concentrated oregano oil supplements should be used cautiously and discussed with your pharmacist or doctor.

Origanum vulgare · Lamiaceae · Leaves and essential oil · Culinary herb, tea, capsules, softgels, liquid oil (oil of oregano), tinctures

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

Oregano: dosing

There is no official, well-established dose for oregano supplements. Products vary widely in strength and in how much carvacrol they contain, so it is hard to compare them.The safest approach is to follow the directions on the product label and not exceed the recommended amount.

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

Read the full Oregano monograph & all interactions
Medication

About Quinidine

What Is Quinidine Used For?

Brand names: Quinaglute Duratabs, Quinaglute, Duraquin, Cardioquin, Cin-Quin, Quinora, Lin-Qin, Quinova, Quinidex Extentabs

Quinidine is used to help restore a normal heart rhythm in people with atrial fibrillation or atrial flutter (irregular, rapid heart rhythms originating in the upper chambers). It is also used on an ongoing basis to reduce how often those episodes come back, in patients whose episodes are frequent and poorly tolerated — but only after other options have been tried first.

Quinidine sulfate oral tablets and quinidine gluconate extended-release oral tablets are both approved for these heart-rhythm uses. Quinidine sulfate tablets are additionally used as part of an approved treatment regimen for life-threatening Plasmodium falciparum malaria, in combination with quinidine gluconate injection (the central component of that regimen). Both formulations may also be used to suppress recurrent, documented life-threatening ventricular arrhythmias (dangerous rapid rhythms in the lower chambers of the heart), such as sustained ventricular tachycardia.

See full Quinidine drug information
Keep checking

Other Drugs & Oregano

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

0Major
208Moderate
0Minor
2,621No known interaction
208 Moderate 2,621 No interaction
Moderate

208 interactions

Showing 60 of 208 moderate interactions — see all 208 on the Oregano page.

No interaction 2,621 drugs checked — show the list

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

Showing the 60 most looked-up of 2,621 medications checked with no known interaction — see the full Oregano list.

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

Oregano References

The 12 references that drive our Oregano 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. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Benito M, Jorro G, Morales C, et al. Labiatae allergy: systemic reactions due to ingestion of oregano and thyme. Ann Allergy Asthma Immunol 1996;76:416-8. PubMed
  3. Chevallier A. Encyclopedia of Herbal Medicine. 2nd ed. New York, NY: DK Publ, Inc., 2000.
  4. Ciganda C, and Laborde A. Herbal infusions used for induced abortion. J Toxicol.Clin Toxicol. 2003;41:235-239. PubMed
  5. Futrell, J. M. and Rietschel, R. L. Spice allergy evaluated by results of patch tests. Cutis 1993;52(5):288-290.
  6. Tognolini, M., Barocelli, E., Ballabeni, V., Bruni, R., Bianchi, A., Chiavarini, M., and Impicciatore, M. Comparative screening of plant essential oils: phenylpropanoid moiety as basic core for antiplatelet activity. Life Sci. 2-23-2006;78(13):1419-1432. PubMed
  7. Goun, E., Cunningham, G., Solodnikov, S., Krasnykch, O., and Miles, H. Antithrombin activity of some constituents from Origanum vulgare. Fitoterapia 2002;73(7-8):692-694. PubMed
  8. Lemhadri, A., Zeggwagh, N. A., Maghrani, M., Jouad, H., and Eddouks, M. Anti-hyperglycaemic activity of the aqueous extract of Origanum vulgare growing wild in Tafilalet region. J Ethnopharmacol. 2004;92(2-3):251-256. PubMed
  9. McCue, P., Vattem, D., and Shetty, K. Inhibitory effect of clonal oregano extracts against porcine pancreatic amylase in vitro. Asia Pac.J Clin.Nutr. 2004;13(4):401-408.
  10. Ragi, J., Pappert, A., Rao, B., Havkin-Frenkel, D., and Milgraum, S. Oregano extract ointment for wound healing: a randomized, double-blind, petrolatum-controlled study evaluating efficacy. J.Drugs Dermatol. 2011;10(10):1168-1172.
  11. Singletary K. Oregano: overview of the literature on health benefits. Nutrition Today 2010;45(3):129-38.
  12. Silva MLAE, Lucarini R, Dos Santos FF, et al. Hypoglycemic effect of rosmarinic acid-rich infusion (RosCE) from Origanum vulgare in alloxan-induced diabetic rats. Nat Prod Res 2022;36(17):4525-4531.

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 Oregano and Quinidine Together: Common Questions

Is it safe to take Oregano with Quinidine?
We do not list a known interaction between Oregano and Quinidine. 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 Oregano and Quinidine have any of the same side effects?
Yes — our sources link each of them separately to 4 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.
How was the Oregano and Quinidine combination checked?
Interactions in our licensed database are recorded against drug classes. Quinidine is filed under 9 classifications, and Oregano has documented interactions with 2 drug classes — none of Quinidine'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 Oregano interact with any other medications?
Yes. Oregano has 208 documented drug interactions in our database — Quinidine 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 Quinidine interact with any supplements?
Yes. Quinidine has documented interactions with 207 supplements in our database — Oregano is not one of them. The Quinidine 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

Oregano monograph Uses, safety profile, and every drug interaction in one place Quinidine drug information The full plain-English guide to this medication Quinidine supplement interactions Every supplement checked against Quinidine, 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 12 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Quinidine and Oregano?

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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.