Drug & supplement interaction

Oleander + Metformin

Metformin brand names: Glucophage, Metformin.

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 Oleander and Metformin 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

Oleander and Metformin

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 Metformin and Oleander 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.

Oleander safety at a glance

Oleander overall Avoid Oleander is highly toxic and can be deadly even in small amounts.
Pregnancy Likely Unsafe When used orally. Oleander has been reported to have abortifacient properties. Also, maternal ingestion of oleander seeds during pregnancy has led to fetal toxi... Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally. Oleander has been reported to have abortifacient properties. Also, maternal ingestion of oleander seeds during pregnancy has led to fetal toxi... 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 Metformin and Oleander? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Metformin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Metformin is filed under 5 classifications — including organic cation transporter 2 (oct2) substrates, antidiabetes drugs, oral drugs. Oleander has documented interactions with 7 drug classes — the most serious being digoxin (lanoxin) (major), diuretic drugs (major) and macrolide antibiotics (major) — and none of Metformin’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

Oleander Does Interact With Other Medications

Oleander has 133 major, 23 moderate known drug interactions in our database — Metformin isn’t one of them. If you take anything else, check it against the full list below.

Major 133 Moderate 23 No known interaction 2,674 (incl. Metformin)
Taking anything else?

Check Another of Your Medications Against Oleander

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

What to actually watch for

No Interaction Found — But Data Suggests Oleander and Metformin 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.

  • Liver problems Worth acting on Additional detail

    Oleander

    “Two cases of jaundice, increased bilirubin, and hepatosplenomegaly have been reported after oleander ingestion.

    Intramuscularly, there is one case report of a patient with cancer who developed hepatotoxicity after receiving daily injections of a specific oleander extract (Anvirzel, Phoenix Biotech) 1.2 mL/m2 for 2 months. Other causes of hepatotoxicity were ruled out.”

    Oleander · Natural Medicines adverse-effect record, reported in cancer.

    2 sources cited
    1. 65420. Samal, K. K., Sahu, H. K., Kar, M. K., Palit, S. K., Kar, B. C., and Sahu, C. S. Yellow oleander (cerbera thevetia) poisoning with jaundice and renal failure. J Assoc Physicians India 1989;37(3):232-233.
    2. 94428. Altan E, Bitik B, Kalpakci Y, ET AL. Probable hepatotoxicity related to Nerium oleander extract in a patient with metastatic synovial sarcoma of the knee. J Altern Complement Med 2009;15:113.

    Metformin

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

  • A change in taste / Diarrhea / Vomiting / Nausea Additional detail

    Oleander

    “Orally, oleander leaves, flowers, and seeds have a bitter taste, and can cause a burning sensation in the mouth, nausea, vomiting, and diarrhea (17,18,3495,65395,65411,65419,65422,65423,65431,65437,94417,94430,94432,94435,94436,98220,103239,103241). Oleander can also cause mucous membrane irritation, increased salivation, abdominal pain and cramping, and buccal erythema.”

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

    6 sources cited
    1. 17. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 3495. Haynes BE, Bessen HA, Wightman WD. Oleander tea: herbal draught of death. Ann Emerg Med 1985;14:350-3. PubMed
    4. 65395. Bose, T. K., Basu, R. K., Biswas, B., De, J. N., Majumdar, B. C., and Datta, S. Cardiovascular effects of yellow oleander ingestion. J Indian Med Assoc. 1999;97(10):407-410.
    5. 65411. Camphausen, C., Haas, N. A., and Mattke, A. C. Successful treatment of oleander intoxication (cardiac glycosides) with digoxin-specific Fab antibody fragments in a 7-year-old child: case report and review of literature. Z Kardiol. 2005;94(12):817-823. PubMed
    6. 65419. Brewster, D. Herbal poisoning: a case report of a fatal yellow oleander poisoning from the Solomon Islands. Ann.Trop.Paediatr. 1986;6(4):289-291. PubMed

    Metformin

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

  • Tiredness / Dizziness Additional detail

    Oleander

    “Orally, oleander can cause weakness, headache, giddiness, dizziness, and malaise or stupor (17,18,3495,65422,65434,65443,65444,94417,94432,94435,94436,98220,103239). It can also cause peripheral neuritis and numbness of the mouth or tongue. There is one case report of a young child who developed irritability and seizures after ingestion of oleander.”

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

    6 sources cited
    1. 17. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 3495. Haynes BE, Bessen HA, Wightman WD. Oleander tea: herbal draught of death. Ann Emerg Med 1985;14:350-3. PubMed
    4. 65422. Saravanapavananthan, N. and Ganeshamoorthy, J. Yellow oleander poisoning--a study of 170 cases. Forensic Sci.Int 1988;36(3-4):247-250. PubMed
    5. 65434. Kakrani, A. L., Rajput, C. S., Khandare, S. K., and Redkar, V. E. Yellow oleander seed poisoning with cardiotoxicity. A case report. Indian Heart J 1981;33(1):31-33.
    6. 65443. Dasgupta, A. and Hart, A. P. Rapid detection of oleander poisoning using fluorescence polarization immunoassay for digitoxin. Effect of treatment with digoxin-specific Fab antibody fragment (ovine). Am J Clin.Pathol. 1997;108(4):411-416.

    Metformin

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

  • A skin rash Additional detail

    Oleander

    “Topically, the sap of freshly cut oleander leaves can cause contact dermatitis. In a case report, a 5-year-old child applied oleander leaves to the face and developed skin erythema, followed by blistering, swelling and partial thickness facial burns. The condition resolved with conservative management.”

    Oleander · Natural Medicines adverse-effect record, reported in burns.

    4 sources cited
    1. 5000. Langford SD, Boor PJ. Oleander toxicity: an examination of human and animal toxic exposures. Toxicology 1996;109:1-13. PubMed
    2. 65432. Apted, J. Oleander dermatitis. Contact Dermatitis 1983;9(4):321.
    3. 65448. Dorsey CS. Plant dermatitis in California. Calif Med 1962;96(6):412-413.
    4. 106425. van Oudtshoorn S, Gera S, Gera P. Paediatric facial burns from oleander leaves. Med J Aust. 2020 Sep;213(6):265-265.e1. Epub 2020 Aug 28. PubMed

    Metformin

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

  • Headache Additional detail

    Oleander

    Recorded for Oleander in the same Natural Medicines adverse-effect record shown under A change in taste / Diarrhea / Vomiting / Nausea above.

    Metformin

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

Reported for Oleander but not commonly for Metformin: yellowing of the skin or eyes, blurred vision, a low platelet count and stomach pain.

Effects for Metformin come from the ADVERSE REACTIONS section of its FDA label; effects for Oleander 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

Oleander in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally. Oleander has been reported to have abortifacient properties. Also, maternal ingestion of oleander seeds during pregnancy has led to fetal toxicity. There is insufficient reliable information available about the safety of topical use of oleander during pregnancy and lactation; 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 Oleander or Metformin

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

This page covers Oleander only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metformin page lists 258 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Siberian Cocklebur (major), Acai (moderate), African Wild Potato (moderate) and Agaricus Mushroom (moderate).

By severity: 2 major · 217 moderate · 39 minor.

From our pharmacist’s overview on the Metformin page

“Siberian cocklebur is the ingredient I most want anyone taking metformin (Glucophage) to know about. It has caused severe low blood sugar in people, documented in humans, and it should not be combined with any glucose-lowering medication.”

Reviewed by 2 · Jul 18, 2026

Open the Metformin interaction page

How much people look this up

Where Oleander and Metformin 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 Oleander
Steady interest

#1,135 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Metformin
Top 1%

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

What is Oleander?

  • Heart failure (traditional)
  • Cancer (investigational)
  • Skin conditions
  • Asthma (folk use)
  • Pain relief (folk use)

Oleander is a highly poisonous ornamental plant, and every part of it can cause life-threatening heart and nervous system effects, even in small amounts. There is no proven safe dose for self-use, and serious poisonings and deaths have occurred from teas, extracts, and accidental ingestion. We strongly advise against using oleander as a supplement.

Nerium oleander · Apocynaceae · Leaves, flowers, stems, and seeds (all parts are toxic) · Extracts, teas, and historically tinctures (not recommended for self-use)

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

Oleander: dosing

There is no safe, established dose of oleander for self-use. Because the amount that might cause an effect is dangerously close to the amount that can poison or kill, no responsible dosing guidance can be given.We do not recommend taking oleander in any form. In nearly all cases, the safe answer is to avoid it entirely.

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

Read the full Oleander monograph & all interactions
Medication

About Metformin

What Is Metformin Used For?

Brand names: Glucophage, Metformin

Metformin is used to improve blood sugar (glucose) control in people with type 2 diabetes mellitus. It is always used together with diet and exercise, not instead of them.

Metformin hydrochloride tablets and oral solution are approved for adults and children 10 years and older. Metformin hydrochloride extended-release tablets — including brands such as Fortamet, Glumetza, and Metformin Hydrochloride Extended Release — are approved for adults only.

See full Metformin drug information
Keep checking

Other Drugs & Oleander

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

133Major
23Moderate
0Minor
2,673No known interaction
133 Major 23 Moderate 2,673 No interaction
Major

133 interactions

Showing 60 of 133 major interactions — see all 133 on the Oleander page.

Moderate

23 interactions

No interaction 2,673 drugs checked — show the list

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

Showing the 60 most looked-up of 2,673 medications checked with no known interaction — see the full Oleander list.

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

Oleander References

The 39 references that drive our Oleander 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. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
  3. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  4. Burnham TH, ed. Drug Facts and Comparisons, Updated Monthly. Facts and Comparisons, St. Louis, MO.
  5. Eddleston M, Rajapakse S, Rajakanthan K, et al. Anti-digoxin Fab fragments in cardiotoxicity induced by ingestion of yellow oleander: a randomized controlled trial. Lancet 2000;355:967-72.
  6. Haynes BE, Bessen HA, Wightman WD. Oleander tea: herbal draught of death. Ann Emerg Med 1985;14:350-3. PubMed
  7. Langford SD, Boor PJ. Oleander toxicity: an examination of human and animal toxic exposures. Toxicology 1996;109:1-13. PubMed
  8. Bose, T. K., Basu, R. K., Biswas, B., De, J. N., Majumdar, B. C., and Datta, S. Cardiovascular effects of yellow oleander ingestion. J Indian Med Assoc. 1999;97(10):407-410.
  9. Camphausen, C., Haas, N. A., and Mattke, A. C. Successful treatment of oleander intoxication (cardiac glycosides) with digoxin-specific Fab antibody fragments in a 7-year-old child: case report and review of literature. Z Kardiol. 2005;94(12):817-823. PubMed
  10. Samal, K. K. Yellow oleander poisoning with jaundice and renal failure. J Assoc Physicians India 1990;38(10):821-822.
  11. Brewster, D. Herbal poisoning: a case report of a fatal yellow oleander poisoning from the Solomon Islands. Ann.Trop.Paediatr. 1986;6(4):289-291. PubMed
  12. Samal, K. K., Sahu, H. K., Kar, M. K., Palit, S. K., Kar, B. C., and Sahu, C. S. Yellow oleander (cerbera thevetia) poisoning with jaundice and renal failure. J Assoc Physicians India 1989;37(3):232-233.
  13. Saravanapavananthan, N. and Ganeshamoorthy, J. Yellow oleander poisoning--a study of 170 cases. Forensic Sci.Int 1988;36(3-4):247-250. PubMed
  14. Blum, L. M. and Rieders, F. Oleandrin distribution in a fatality from rectal and oral Nerium oleander extract administration. J Anal.Toxicol. 1987;11(5):219-221. PubMed
  15. Kaojarern, S., Sukhupunyarak, S., and Mokkhavesa, C. Oleander Yee tho poisoning. J Med Assoc.Thai. 1986;69(2):108-112.

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 Oleander and Metformin Together: Common Questions

Is it safe to take Oleander with Metformin?
We do not list a known interaction between Oleander and Metformin. 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 Oleander and Metformin have any of the same side effects?
Yes — our sources link each of them separately to 9 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 Oleander and Metformin combination checked?
Interactions in our licensed database are recorded against drug classes. Metformin is filed under 5 classifications, and Oleander has documented interactions with 7 drug classes — none of Metformin'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 Oleander interact with any other medications?
Yes. Oleander has 156 documented drug interactions in our database — Metformin 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 Metformin interact with any supplements?
Yes. Metformin has documented interactions with 258 supplements in our database — Oleander is not one of them. The Metformin 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

Oleander monograph Uses, safety profile, and every drug interaction in one place Metformin drug information The full plain-English guide to this medication Metformin supplement interactions Every supplement checked against Metformin, 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 39 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Metformin and Oleander?

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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.