Drug & supplement interaction

Willow Bark + Cefdinir

Cefdinir brand name: Omnicef.

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 Willow Bark and Cefdinir 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

Willow Bark and Cefdinir

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 Cefdinir and Willow Bark 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.

Willow Bark safety at a glance

Willow Bark overall Use caution Generally tolerated short-term by healthy adults, but it acts like aspirin and is not safe for everyone.
Pregnancy Avoid Avoid during pregnancy because its aspirin-like action may pose risks, especially later in pregnancy.
Breastfeeding Possibly Unsafe When used orally. Willow bark contains salicylates which are excreted in breast milk and have been linked to adverse effects in breast-fed infants. 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 Cefdinir and Willow Bark? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Cefdinir

Interactions in our licensed database are recorded against drug classes, not just single drug names. Cefdinir is filed under 6 classifications — including organic anion transporter 3 (oat3) substrates, organic anion transporter 1 (oat1) substrates, antibiotic drugs. Willow Bark has documented interactions with 5 drug classes — the most serious being acetazolamide (moderate), anticoagulant/antiplatelet drugs (moderate) and aspirin (moderate) — and none of Cefdinir’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

Willow Bark Does Interact With Other Medications

Willow Bark has 127 moderate known drug interactions in our database — Cefdinir isn’t one of them. If you take anything else, check it against the full list below.

Moderate 127 No known interaction 2,703 (incl. Cefdinir)
Taking anything else?

Check Another of Your Medications Against Willow Bark

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

What to actually watch for

No Interaction Found — But Data Suggests Willow Bark and Cefdinir 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. 5 of them are worth acting on rather than waiting out — marked below.

  • Kidney problems / A severe allergic reaction / An allergic reaction Worth acting on reported in 11.1% of FDA reports for Cefdinir Additional detail

    Willow Bark

    “Orally, willow bark seems to be well tolerated.

    Most Common Adverse Effects:

    Orally: Diarrhea, dyspepsia, heartburn, and vomiting. May cause itching and rash in sensitive individuals.

    Serious Adverse Effects (Rare):

    Orally: Gastrointestinal bleeding and renal impairment. May cause serious allergic reactions, including anaphylaxis, in people who are allergic to aspirin.”

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

    Cefdinir

    Listed in the ADVERSE REACTIONS section of the FDA label for Cefdinir, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Bleeding in the gut / Bleeding or bruising Worth acting on Additional detail

    Willow Bark

    “Orally, willow bark extract can cause gastrointestinal adverse effects, but these appear to be less frequent than those caused by NSAIDs. Examples include diarrhea, heartburn, vomiting, and dyspepsia. In a case report of a child, severe gastrointestinal bleeding occurred following use of a specific syrup (FreddoBaby), which contained ribwort plantain, licorice, willow bark, black elder, meadowsweet, and propolis.”

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

    5 sources cited
    1. 12474. Schmid B, Ludtke R, Selbmann HK, et al. Efficacy and tolerability of a standardized willow bark extract in patients with osteoarthritis: randomized placebo-controlled, double blind clinical trial. Phytother Res 2001;15:344-50. PubMed
    2. 12475. Biegert C, Wagner I, Ludtke R, et al. Efficacy and safety of willow bark extract in the treatment of osteoarthritis and rheumatoid arthritis: results of 2 randomized double-blind controlled trials. J Rheumatol 2004;31:2121-30.
    3. 12804. Chrubasik S, Kunzel O, Model A, et al. Treatment of low back pain with a herbal or synthetic anti-rheumatic: a randomized controlled study. Willow bark extract for low back pain. Rheumatology (Oxford) 2001;40:1388-93. PubMed
    4. 86459. Chrubasik, S., Kunzel, O., Black, A., Conradt, C., and Kerschbaumer, F. Potential economic impact of using a proprietary willow bark extract in outpatient treatment of low back pain: an open non-randomized study. Phytomedicine 2001;8(4):241-251. PubMed
    5. 86477. <p>Moro PA, Flacco V, Cassetti F, Clementi V, Colombo ML, Chiesa GM, Menniti-Ippolito F, Raschetti R, Santuccio C. Hypovolemic shock due to severe gastrointestinal bleeding in a child taking an herbal syrup. Ann Ist Super Sanita. 2011;47(3):278-83.</p>

    Cefdinir

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

  • Stomach upset / Diarrhea reported in 6.9% of FDA reports for Cefdinir Additional detail

    Willow Bark

    Recorded for Willow Bark in the same Natural Medicines adverse-effect record shown under Kidney problems / A severe allergic reaction / An allergic reaction above.

    Cefdinir

    Listed in the ADVERSE REACTIONS section of the FDA label for Cefdinir, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Itching / A skin rash Additional detail

    Willow Bark

    “Orally, willow bark may cause itching and rash in some people due to allergy.”

    Willow Bark · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    5 sources cited
    1. 6456. Chrubasik S, Eisenberg E, Balan E, et al. Treatment of low back pain exacerbations with willow bark extract: a randomized double-blind study. Am J Med 2000;109:9-14. PubMed
    2. 12474. Schmid B, Ludtke R, Selbmann HK, et al. Efficacy and tolerability of a standardized willow bark extract in patients with osteoarthritis: randomized placebo-controlled, double blind clinical trial. Phytother Res 2001;15:344-50. PubMed
    3. 12475. Biegert C, Wagner I, Ludtke R, et al. Efficacy and safety of willow bark extract in the treatment of osteoarthritis and rheumatoid arthritis: results of 2 randomized double-blind controlled trials. J Rheumatol 2004;31:2121-30.
    4. 12804. Chrubasik S, Kunzel O, Model A, et al. Treatment of low back pain with a herbal or synthetic anti-rheumatic: a randomized controlled study. Willow bark extract for low back pain. Rheumatology (Oxford) 2001;40:1388-93. PubMed
    5. 86459. Chrubasik, S., Kunzel, O., Black, A., Conradt, C., and Kerschbaumer, F. Potential economic impact of using a proprietary willow bark extract in outpatient treatment of low back pain: an open non-randomized study. Phytomedicine 2001;8(4):241-251. PubMed

    Cefdinir

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

  • Dizziness Additional detail

    Willow Bark

    “Orally, willow bark may cause headache and dizziness. In a clinical trial evaluating a combination product containing willow bark, black cohosh, sarsaparilla, poplar bark, and guaiac wood (Reumalex), severe headaches occurred.”

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

    2 sources cited
    1. 12804. Chrubasik S, Kunzel O, Model A, et al. Treatment of low back pain with a herbal or synthetic anti-rheumatic: a randomized controlled study. Willow bark extract for low back pain. Rheumatology (Oxford) 2001;40:1388-93. PubMed
    2. 35946. Mills SY, Jacoby RK, Chacksfield M, Willoughby M. Effect of a proprietary herbal medicine on the relief of chronic arthritic pain: a double-blind study. Br J Rheumatol 1996;35:874-8. PubMed

    Cefdinir

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

Showing the 10 most notable of 12 shared effects — ranked by how unusual each one is, not just whether both lists mention it.

Reported for Willow Bark but not commonly for Cefdinir: heartburn.

Effects for Cefdinir come from the ADVERSE REACTIONS section of its FDA label; effects for Willow Bark come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 7,629 voluntary FDA FAERS reports for Cefdinir that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Willow Bark in Pregnancy & Breastfeeding

Lactation Possibly Unsafe

When used orally. Willow bark contains salicylates which are excreted in breast milk and have been linked to adverse effects in breast-fed infants.

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

Overlapping uses

What Cefdinir Is Prescribed For, and What Willow Bark Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Cefdinir is a prescription medicine with approved uses on its FDA label. Willow Bark is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Cefdinir is prescribed for: Cefdinir treats mild to moderate bacterial infections in adults, adolescents, and children caused by susceptible bacteria. It is used for community-acquired pneumonia, acute exacerbations of chronic bronchitis, acute maxillary sinusitis (sinus infection), pharyngitis/tonsillitis (strep throat), and uncomplicated skin and skin structure infections. In pediatric patients (ages 6 months through 12 years), cefdinir is also used to treat acute bacterial otitis media (middle ear infection). It should only be used for infections that are proven or strongly suspected to be caused by bacteria — not for viral illnesses like the common cold.

Willow Bark has been studied for:

  • Common cold studied, not established Willow Bark has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Willow Bark for common cold

    Although there has been interest in using oral willow bark for common cold symptoms, there is insufficient reliable information about the clinical effects of willow bark for this purpose.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Cefdinir on your own; if you are taking Willow Bark for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Willow Bark or Cefdinir

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

This page covers Willow Bark only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cefdinir page lists 60 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 3 major · 46 moderate · 11 minor.

From our pharmacist’s overview on the Cefdinir page

“Cefdinir (Omnicef) is a short-course antibiotic for ear, sinus, throat, and skin infections, and three of its 60 supplement interactions on file are rated major and deserve genuine care. Two herbs, Siberian cocklebur and asarabacca, can damage the kidneys, an added strain nobody needs while fighting an infection.”

Reviewed by 2 · Jul 18, 2026

Open the Cefdinir interaction page

One more smart check

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

We hold 43 real supplement products containing Willow Bark, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Willow Bark. Even though Willow Bark itself has no known interaction with Cefdinir, 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 Willow Bark and Cefdinir 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 Willow Bark
Steady interest

#1,002 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Cefdinir
Steady interest

#1,571 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 Willow Bark reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Willow Bark and Cefdinir 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 Willow Bark

What is Willow Bark?

  • Low back pain
  • Osteoarthritis joint pain
  • Headache
  • Fever
  • General aches and inflammation

Willow bark is a traditional plant remedy that contains salicin, a compound related to aspirin, and is most often used for pain and inflammation. Some evidence suggests it may modestly help low back pain and joint pain, but the research is limited and the right dose is not well standardized. Because it acts like aspirin, people with aspirin allergies, bleeding problems, or who are pregnant should be cautious and talk to a pharmacist or doctor first.

Salix alba · Salicaceae · Bark · Capsules, tablets, dried bark for tea, liquid extracts, standardized extracts

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

Willow Bark: dosing

There is no single official dose for willow bark. Products vary widely, and many are standardized to a certain amount of salicin, which is the part researchers usually measure.Because strength differs from brand to brand, the best approach is to follow the directions on the product label and not exceed them. They can help you decide whether willow bark is appropriate and how much is reasonable for you.

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

Read the full Willow Bark monograph & all interactions
Medication

About Cefdinir

What Is Cefdinir Used For?

Brand name: Omnicef

Cefdinir treats mild to moderate bacterial infections in adults, adolescents, and children caused by susceptible bacteria. It is used for community-acquired pneumonia, acute exacerbations of chronic bronchitis, acute maxillary sinusitis (sinus infection), pharyngitis/tonsillitis (strep throat), and uncomplicated skin and skin structure infections.

In pediatric patients (ages 6 months through 12 years), cefdinir is also used to treat acute bacterial otitis media (middle ear infection). It should only be used for infections that are proven or strongly suspected to be caused by bacteria — not for viral illnesses like the common cold.

Most-Reported Side Effects for Cefdinir

From FAERS, the FDA’s public side-effect reporting system (7,629 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 530 reports
Chronic kidney disease 485 reports
Pneumonia 482 reports
Fatigue 462 reports
Nausea 400 reports
See full Cefdinir drug information
Keep checking

Other Drugs & Willow Bark

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

0Major
127Moderate
0Minor
2,702No known interaction
127 Moderate 2,702 No interaction
Moderate

127 interactions

Showing 60 of 127 moderate interactions — see all 127 on the Willow Bark page.

No interaction 2,702 drugs checked — show the list

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

Showing the 60 most looked-up of 2,702 medications checked with no known interaction — see the full Willow Bark list.

See the full Willow Bark interactions page
See every supplement checked against Cefdinir, ranked by severity
Evidence & sources

Willow Bark References

The 12 references that drive our Willow Bark 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. Chrubasik S, Eisenberg E, Balan E, et al. Treatment of low back pain exacerbations with willow bark extract: a randomized double-blind study. Am J Med 2000;109:9-14. PubMed
  2. Schmid B, Ludtke R, Selbmann HK, et al. Efficacy and tolerability of a standardized willow bark extract in patients with osteoarthritis: randomized placebo-controlled, double blind clinical trial. Phytother Res 2001;15:344-50. PubMed
  3. Biegert C, Wagner I, Ludtke R, et al. Efficacy and safety of willow bark extract in the treatment of osteoarthritis and rheumatoid arthritis: results of 2 randomized double-blind controlled trials. J Rheumatol 2004;31:2121-30.
  4. Unsworth J, d'Assis-Fonseca A, Beswick DT, Blake DR. Serum salicylate levels in a breast fed infant. Ann Rheum Dis 1987;46:638-9. PubMed
  5. Clark JH, Wilson WG. A 16-day-old breast-fed infant with metabolic acidosis caused by salicylate. Clin Pediatr (Phila) 1981;20:53-4. PubMed
  6. Chrubasik S, Kunzel O, Model A, et al. Treatment of low back pain with a herbal or synthetic anti-rheumatic: a randomized controlled study. Willow bark extract for low back pain. Rheumatology (Oxford) 2001;40:1388-93. PubMed
  7. Schmid B, Kotter I, Heide L. Pharmacokinetics of salicin after oral administration of a standardised willow bark extract. Eur J Clin Pharmacol. 2001;57:387-91. PubMed
  8. Krivoy N, Pavlotzky E, Chrubasik S, et al. Effect of salicis cortex extract on human platelet aggregation. Planta Med 2001;67:209-12. PubMed
  9. Mills SY, Jacoby RK, Chacksfield M, Willoughby M. Effect of a proprietary herbal medicine on the relief of chronic arthritic pain: a double-blind study. Br J Rheumatol 1996;35:874-8. PubMed
  10. Chrubasik, S., Kunzel, O., Black, A., Conradt, C., and Kerschbaumer, F. Potential economic impact of using a proprietary willow bark extract in outpatient treatment of low back pain: an open non-randomized study. Phytomedicine 2001;8(4):241-251. PubMed
  11. <p>Moro PA, Flacco V, Cassetti F, Clementi V, Colombo ML, Chiesa GM, Menniti-Ippolito F, Raschetti R, Santuccio C. Hypovolemic shock due to severe gastrointestinal bleeding in a child taking an herbal syrup. Ann Ist Super Sanita. 2011;47(3):278-83.</p>
  12. Sweeney, K. R., Chapron, D. J., Brandt, J. L., Gomolin, I. H., Feig, P. U., and Kramer, P. A. Toxic interaction between acetazolamide and salicylate: case reports and a pharmacokinetic explanation. Clin Pharmacol Ther 1986;40(5):518-524.

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 Willow Bark and Cefdinir Together: Common Questions

Is it safe to take Willow Bark with Cefdinir?
We do not list a known interaction between Willow Bark and Cefdinir. 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 Willow Bark and Cefdinir have any of the same side effects?
Yes — our sources link each of them separately to 10 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.
Are Willow Bark and Cefdinir used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Willow Bark in each. That is a conversation for your prescriber, especially if Cefdinir is being adjusted to a target.
How was the Willow Bark and Cefdinir combination checked?
Interactions in our licensed database are recorded against drug classes. Cefdinir is filed under 6 classifications, and Willow Bark has documented interactions with 5 drug classes — none of Cefdinir'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 Willow Bark interact with any other medications?
Yes. Willow Bark has 127 documented drug interactions in our database — Cefdinir 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 Cefdinir interact with any supplements?
Yes. Cefdinir has documented interactions with 60 supplements in our database — Willow Bark is not one of them. The Cefdinir 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

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

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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.