Drug & supplement interaction

Daffodil + Levothyroxine

Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, 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 Daffodil and Levothyroxine 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 Levothyroxine 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

Daffodil and Levothyroxine

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 Levothyroxine and Daffodil 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 Daffodil at all — not against Levothyroxine, 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.

Daffodil safety at a glance

Daffodil overall Avoid All parts of the daffodil are toxic and should not be eaten or used as a homemade supplement.
Pregnancy Likely Unsafe When used orally or topically; avoid using. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally or topically; 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 Levothyroxine and Daffodil? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Daffodil and Levothyroxine 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.

  • Seizures Worth acting on Additional detail

    Daffodil

    “Daffodil is generally regarded as unsafe for use. Any benefits of therapy may not outweigh the risk of toxicity.

    Serious Adverse Effects (Rare):

    Orally: Irritation and swelling of the mouth, tongue, and throat, and sudden onset of vomiting, diarrhea, and abdominal pain. Large doses have also been reported to cause blurred vision, coma, convulsions, dizziness, headache, hypotension, salivation, sweating, and tremors.”

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

    “Orally, large doses of daffodil can cause toxicity, including dizziness, headache, tremors, convulsions, and coma.”

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

    1 source cited
    1. 101223. Matulkova P, Gobin M, Evans M, et al. Gastro-intestinal poisoning due to consumption of daffodils mistaken for vegetables at commercial markets, Bristol, United Kingdom. Clin Toxicol (Phila) 2012;50(8):788-90. doi: 10.3109/15563650.2012.718350. PubMed

    Levothyroxine

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

  • Sweating Additional detail

    Daffodil

    “Topically, skin contact with any part of the daffodil plant can cause dermatitis, sometimes referred to as "daffodil itch" or "lily rash" (18,5004,5005).

    Orally, large doses of daffodil can cause toxicity, including excessive sweating.”

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

    4 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 5004. Bruynzeel DP. Bulb dermatitis. Dermatological problems in the flower bulb industries. Contact Dermatitis 1997;37:70-7.
    3. 5005. Bruynzeel DP, de Boer EM, Brouwer EJ, et al. Dermatitis in bulb growers. Contact Dermatitis 1993;29:11-5. PubMed
    4. 101223. Matulkova P, Gobin M, Evans M, et al. Gastro-intestinal poisoning due to consumption of daffodils mistaken for vegetables at commercial markets, Bristol, United Kingdom. Clin Toxicol (Phila) 2012;50(8):788-90. doi: 10.3109/15563650.2012.718350. PubMed

    Levothyroxine

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

  • Stomach pain / Diarrhea / Vomiting Additional detail

    Daffodil

    “Orally, daffodil can cause irritation and swelling of the mouth, tongue, and throat, as well as sudden onset of vomiting, diarrhea, and abdominal pain. Vomiting and diarrhea often limit the progression of symptoms, and adults typically recover within 3-4 hours. Large doses of daffodil can cause toxicity, including excessive salivation (18,19,101223).”

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

    3 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 19. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
    3. 101223. Matulkova P, Gobin M, Evans M, et al. Gastro-intestinal poisoning due to consumption of daffodils mistaken for vegetables at commercial markets, Bristol, United Kingdom. Clin Toxicol (Phila) 2012;50(8):788-90. doi: 10.3109/15563650.2012.718350. PubMed

    Levothyroxine

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

  • A skin rash Additional detail

    Daffodil

    Recorded for Daffodil in the same Natural Medicines adverse-effect record shown under Sweating above.

    Levothyroxine

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

  • Headache Additional detail

    Daffodil

    Recorded for Daffodil in the same Natural Medicines adverse-effect record shown under Seizures above.

    Levothyroxine

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

Reported for Daffodil but not commonly for Levothyroxine: blurred vision, low blood pressure, dizziness and swelling.

Effects for Levothyroxine come from the ADVERSE REACTIONS section of its FDA label; effects for Daffodil 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

Daffodil in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally or topically; 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 Levothyroxine Products Have a Food Rule — Daffodil Should Not Break It

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

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 Daffodil or Levothyroxine

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

This page covers Daffodil only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine page lists 50 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Tiratricol (major), Acetyl-l-carnitine (moderate), Alpha-lipoic Acid (moderate) and Ascophyllum Nodosum (moderate).

By severity: 2 major · 39 moderate · 9 minor.

From our pharmacist’s overview on the Levothyroxine page

“Levothyroxine replaces a hormone your body measures in tiny amounts, so small shifts in its blood level show up in how you feel, and I treat this list with genuine care. Nearly everything on it does one of two things: blocks the pill from being absorbed in the gut, the way everyday minerals like calcium do by binding it into complexes,…”

Reviewed by 2 · Jul 18, 2026

Open the Levothyroxine interaction page

How much people look this up

Where Daffodil and Levothyroxine 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 Daffodil
Top half

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

29 days ago today
Medication Levothyroxine
Top 10

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

What is Daffodil?

  • Traditional anti-inflammatory remedy
  • Folk use for tumors and skin growths
  • Source of galantamine for memory/Alzheimer's
  • Antimicrobial folk use
  • Topical traditional remedies

Daffodil is a beautiful but toxic plant that contains alkaloids, including the one used to make the Alzheimer's drug galantamine. It is not safe to take as a homemade supplement, and all parts of the plant—especially the bulb—can cause serious poisoning if eaten. Leave any medicinal use to standardized, regulated medications prescribed by a doctor.

Narcissus pseudonarcissus · Amaryllidaceae · Bulb, flower, and leaves (source of certain alkaloids) · Not commonly available as a consumer supplement; the plant is the source of the prescription drug galantamine

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

Daffodil: dosing

There is no safe established dose of daffodil as a supplement, and it should not be taken by mouth. Because the whole plant is toxic, no amount can be recommended for self-treatment.The only proven medical use linked to this plant is the prescription drug galantamine, which is manufactured to a precise, standardized dose and must be prescribed and monitored by a healthcare provider.

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

Read the full Daffodil monograph & all interactions
Medication

About Levothyroxine

What Is Levothyroxine Used For?

Brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, Levo-T, Eltroxin, Estre, Levothyroxine, Novothyrox, Levolet

Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain.

It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.

See full Levothyroxine drug information
Keep checking

Other Drugs & Daffodil

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

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

Daffodil References

The 5 references that drive our Daffodil 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. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Bruynzeel DP. Bulb dermatitis. Dermatological problems in the flower bulb industries. Contact Dermatitis 1997;37:70-7.
  4. Bruynzeel DP, de Boer EM, Brouwer EJ, et al. Dermatitis in bulb growers. Contact Dermatitis 1993;29:11-5. PubMed
  5. Matulkova P, Gobin M, Evans M, et al. Gastro-intestinal poisoning due to consumption of daffodils mistaken for vegetables at commercial markets, Bristol, United Kingdom. Clin Toxicol (Phila) 2012;50(8):788-90. doi: 10.3109/15563650.2012.718350. 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 Daffodil and Levothyroxine Together: Common Questions

Is it safe to take Daffodil with Levothyroxine?
We do not list a known interaction between Daffodil and Levothyroxine. 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 Daffodil and Levothyroxine have any of the same side effects?
Yes — our sources link each of them separately to 7 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 Daffodil and Levothyroxine at the same time of day?
At least one FDA label for a product containing Levothyroxine 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 Levothyroxine on its own and move Daffodil 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 Levothyroxine interact with any supplements?
Yes. Levothyroxine has documented interactions with 50 supplements in our database — Daffodil is not one of them. The Levothyroxine 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

Daffodil monograph Uses, safety profile, and every drug interaction in one place Levothyroxine drug information The full plain-English guide to this medication Levothyroxine supplement interactions Every supplement checked against Levothyroxine, 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 Levothyroxine and Daffodil?

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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.