Drug & supplement interaction

Tannic Acid + Fosfomycin

Fosfomycin brand name: Monurol.

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 Tannic Acid and Fosfomycin 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

Tannic Acid and Fosfomycin

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 Fosfomycin and Tannic Acid 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 Tannic Acid at all — not against Fosfomycin, 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.

Tannic Acid safety at a glance

Tannic Acid overall Use caution Generally used topically in small amounts, but absorption through broken skin or large burns can harm the liver.
Pregnancy Possibly Unsafe When used topically on damaged or broken skin. There is insufficient reliable information available about the safety of tannic acid when used orally during preg... Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used topically on damaged or broken skin. There is insufficient reliable information available about the safety of tannic acid when used orally during preg... 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 Fosfomycin and Tannic Acid? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Tannic Acid and Fosfomycin 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.

  • Vomiting / Nausea Additional detail

    Tannic Acid

    “Orally, large amounts of tannic acid can cause gastric irritation, nausea, and vomiting (11). Extensive use of tannins on burns or in enemas has been associated with fatal liver damage (11). However, this toxicity may be due to digallic acid, an impurity that is sometimes found in tannic acid (11).”

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

    1 source cited
    1. 11. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.

    “Orally, large amounts of tannic acid can cause gastric irritation, nausea, and vomiting (11).”

    Tannic Acid · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    1 source cited
    1. 11. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.

    Fosfomycin

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

Reported for Tannic Acid but not commonly for Fosfomycin: stomach upset and liver problems.

Effects for Fosfomycin come from the ADVERSE REACTIONS section of its FDA label; effects for Tannic Acid 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

Tannic Acid in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used topically on damaged or broken skin. There is insufficient reliable information available about the safety of tannic acid when used orally during pregnancy and lactation; avoid using amounts greater than those found in foods.

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

Everything else you take

See Every Supplement That Interacts With Fosfomycin

This page covers Tannic Acid only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fosfomycin page lists 44 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Bacillus Coagulans (moderate), Bacillus Subtilis (moderate), Bifidobacterium Animalis Subsp. Lactis (moderate) and Bifidobacterium Bifidum (moderate).

By severity: 1 major · 33 moderate · 10 minor.

From our pharmacist’s overview on the Fosfomycin page

“Fosfomycin (Monurol) is often given as a single sachet to knock out a bladder infection, so you get one chance to absorb the full dose, and that is exactly where this list deserves real care. The clearest hazard is activated charcoal, which binds medicines in the gut and can cut how much fosfomycin your body actually takes in.”

Reviewed by 2 · Jul 18, 2026

Open the Fosfomycin interaction page

How much people look this up

Where Tannic Acid and Fosfomycin 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 Tannic Acid
Steady interest

#1,250 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Fosfomycin
Steady interest

#1,960 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 Tannic Acid reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Tannic Acid and Fosfomycin 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 Tannic Acid

What is Tannic Acid?

  • Minor skin irritation and weeping rashes
  • Sore throat and mouth sores
  • Minor burns and blisters
  • Astringent for skin
  • Hemorrhoids

Tannic acid is a plant-derived astringent used mostly on the skin and in the mouth to dry out and tighten tissue. There is some traditional and topical use, but high-quality evidence for most uses is limited, and it can be harmful if too much is absorbed, especially on broken skin or burns.

Tannins extracted from plant sources such as oak galls, bark, and certain seeds and leaves · Topical powders and solutions, throat lozenges, gargles, suppositories, and some over-the-counter skin products

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

Tannic Acid: dosing

There is no well-established standard dose of tannic acid for supplement use. The amount varies widely depending on the product and how it is used (for example, a skin solution versus a lozenge).The safest approach is to follow the directions on the product label and not apply it to large areas of broken or burned skin.

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

Read the full Tannic Acid monograph & all interactions
Medication

About Fosfomycin

What Is Fosfomycin Used For?

Brand name: Monurol

Fosfomycin is an antibiotic used to treat urinary tract infections (UTIs) caused by specific bacteria. The right form depends on how serious the infection is.

Oral forms (Fosfomycin Tromethamine and Monurol) are approved only for uncomplicated UTIs — also called acute cystitis — in women 18 and older, caused by E. coli or Enterococcus faecalis. They are not for kidney infections or abscesses around the kidney. Contepo (intravenous) is approved for adults 18 and older with complicated UTIs, including acute pyelonephritis (kidney infection), caused by susceptible E. coli or Klebsiella pneumoniae.

See full Fosfomycin drug information
Keep checking

Other Drugs & Tannic Acid

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

See the full Tannic Acid interactions page
See every supplement checked against Fosfomycin, ranked by severity
Evidence & sources

Tannic Acid References

The 8 references that drive our Tannic Acid 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. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  3. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  4. Laslett, L. L., Quinn, S. J., Darian-Smith, E., Kwok, M., Fedorova, T., Korner, H., Steels, E., March, L., and Jones, G. Treatment with 4Jointz reduces knee pain over 12 weeks of treatment in patients with clinical knee osteoarthritis: a randomised contr
  5. Smith DB, Jacobson BH. Effect of a blend of comfrey root extract (Symphytum officinale L.) and tannic acid creams in the treatment of osteoarthritis of the knee: randomized, placebo-controlled, double-blind, multiclinical trials. J Chiropr Med. 2011;10(3) PubMed
  6. Goh CL, Yoyong K. A comparison of topical tannic acid versus iontophoresis in the medical treatment of palmar hyperhidrosis. Singapore Med J. 1996;37(5):466-8.
  7. Kołodziej M, Bebenek D, Konarska Z, Szajewska H. Gelatine tannate in the management of acute gastroenteritis in children: a randomised controlled trial. BMJ Open. 2018;8(5):e020205. PubMed
  8. Mennini M, Tolone C, Frassanito A, Midulla F, Cucchiara S, Aloi M. Gelatin tannate for acute childhood gastroenteritis: a randomized, single-blind controlled trial. Paediatr Drugs. 2017 Apr;19(2):131-137. 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 Tannic Acid and Fosfomycin Together: Common Questions

Is it safe to take Tannic Acid with Fosfomycin?
We do not list a known interaction between Tannic Acid and Fosfomycin. 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 Tannic Acid and Fosfomycin have any of the same side effects?
Yes — our sources link each of them separately to 2 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.
Does Fosfomycin interact with any supplements?
Yes. Fosfomycin has documented interactions with 44 supplements in our database — Tannic Acid is not one of them. The Fosfomycin 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

Tannic Acid monograph Uses, safety profile, and every drug interaction in one place Fosfomycin drug information The full plain-English guide to this medication Fosfomycin supplement interactions Every supplement checked against Fosfomycin, 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 8 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Fosfomycin and Tannic Acid?

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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.