Drug & supplement interaction

Manna + Metronidazole

Metronidazole brand names: Flagyl, Protostat, Metronidazole, Nidazol, Trikacide, 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 Manna and Metronidazole 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

Manna and Metronidazole

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 Metronidazole and Manna 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.

Manna safety at a glance

Manna overall Use caution Generally mild but can cause loose stools, gas, and cramping, especially at higher amounts.
Pregnancy Use caution Not well studied in pregnancy; use only under medical supervision.
Breastfeeding Use caution Little safety information exists, so caution is advised while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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

Why No Interaction Is Listed for Metronidazole

Interactions in our licensed database are recorded against drug classes, not just single drug names. Metronidazole is filed under 8 classifications — including cytochrome p450 2c9 (cyp2c9) inhibitors, qt interval-prolonging drugs, cytochrome p450 3a4 (cyp3a4) inhibitors. Manna has documented interactions with 4 drug classes — the most serious being digoxin (lanoxin) (moderate), diuretic drugs (moderate) and stimulant laxatives (moderate) — and none of Metronidazole’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

Manna Does Interact With Other Medications

Manna has 99 moderate known drug interactions in our database — Metronidazole isn’t one of them. If you take anything else, check it against the full list below.

Moderate 99 No known interaction 2,731 (incl. Metronidazole)
Taking anything else?

Check Another of Your Medications Against Manna

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

What to actually watch for

No Interaction Found — But Data Suggests Manna and Metronidazole May Share a Side Effect

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.

  • Nausea reported in 7.4% of FDA reports for Metronidazole Additional detail

    Manna

    “Orally, manna has been reported to cause flatulence and nausea (2,18).”

    Manna · Natural Medicines adverse-effect record, reported in flatulence.

    2 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Metronidazole

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

Reported for Manna but not commonly for Metronidazole: bloating or gas.

Effects for Metronidazole come from the ADVERSE REACTIONS section of its FDA label; effects for Manna come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 64,630 voluntary FDA FAERS reports for Metronidazole 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.

From our Q&A

Questions About Manna or Metronidazole

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

This page covers Manna only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metronidazole page lists 83 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), Cesium (major) and Ephedra (major).

By severity: 7 major · 63 moderate · 13 minor.

From our pharmacist’s overview on the Metronidazole page

“Metronidazole (Flagyl) can stretch the heart's QT interval on its own, and most of the seven major-rated interactions among its 83 flagged supplement ingredients do the same thing, so I read this list with more wariness than most antibiotics earn. Grapefruit and ephedra stand out for adding to that heart-rhythm risk, while activated ch…”

Reviewed by 2 · Jul 18, 2026

Open the Metronidazole interaction page

One more smart check

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

We hold 27 real supplement products containing Manna, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Manna. Even though Manna itself has no known interaction with Metronidazole, 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 Manna and Metronidazole 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 Manna
Top half

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

29 days ago today
Medication Metronidazole
Top 25%

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

What is Manna?

Manna
  • Gentle constipation relief
  • Mild laxative for children and elderly
  • Natural sweetener
  • Occasional bowel softening

Manna is the dried, sweet sap of the flowering ash tree (Fraxinus ornus) and is best known as a gentle, mild laxative because it contains a sugar alcohol called mannitol. It is generally considered mild and is sometimes used for occasional constipation, but high-quality modern studies are limited, so talk with your pharmacist or doctor before using it.

Fraxinus ornus · Oleaceae · Dried sap (exudate) from the bark and stems · Dried flakes or pieces, syrup, powder, and as an ingredient in laxative products

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

Manna: dosing

There is no official standardized dose of manna for supplement use. Amounts have traditionally varied based on the person's age and how strong a laxative effect is needed, with smaller amounts used for children.If you choose to use a manna product, follow the directions on the label and start with the lowest amount.

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

Read the full Manna monograph & all interactions
Medication

About Metronidazole

What Is Metronidazole Used For?

Brand names: Flagyl, Protostat, Metronidazole, Nidazol, Trikacide, MetroGel, Flagyl IV, Metronidazole Redi-Infusion, Flagyl IV RTU, Metro IV, Anabact, Metrosa, Metrotop, Noritate, Rozex Cream, Rozex Gel, Zyomet, Likmez

Metronidazole treats three main types of infections. It's used for trichomoniasis (a sexually transmitted parasitic infection), amebiasis (an intestinal or liver infection caused by a parasite), and serious anaerobic bacterial infections — infections caused by bacteria that thrive without oxygen, which can affect the abdomen, skin, bones, lungs, and other areas.

Because sexual partners can pass trichomoniasis back and forth, both partners are typically treated at the same time, even if one has no symptoms.

Most-Reported Side Effects for Metronidazole

From FAERS, the FDA’s public side-effect reporting system (64,630 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Nausea 4,812 reports
Diarrhea 4,197 reports
Vomiting 3,393 reports
Fever 3,294 reports
Drug hypersensitivity 3,160 reports
See full Metronidazole drug information
Keep checking

Other Drugs & Manna

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

0Major
99Moderate
0Minor
2,730No known interaction
99 Moderate 2,730 No interaction
Moderate

99 interactions

Showing 60 of 99 moderate interactions — see all 99 on the Manna page.

No interaction 2,730 drugs checked — show the list

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

Showing the 60 most looked-up of 2,730 medications checked with no known interaction — see the full Manna list.

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

Manna References

The 3 references that drive our Manna 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

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 Manna and Metronidazole Together: Common Questions

Is it safe to take Manna with Metronidazole?
We do not list a known interaction between Manna and Metronidazole. 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 Manna and Metronidazole have any of the same side effects?
Yes — our sources link each of them separately to one 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 Manna and Metronidazole combination checked?
Interactions in our licensed database are recorded against drug classes. Metronidazole is filed under 8 classifications, and Manna has documented interactions with 4 drug classes — none of Metronidazole'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 Manna interact with any other medications?
Yes. Manna has 99 documented drug interactions in our database — Metronidazole 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 Metronidazole interact with any supplements?
Yes. Metronidazole has documented interactions with 83 supplements in our database — Manna is not one of them. The Metronidazole 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

Manna monograph Uses, safety profile, and every drug interaction in one place Metronidazole drug information The full plain-English guide to this medication Metronidazole supplement interactions Every supplement checked against Metronidazole, 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Metronidazole and Manna?

Our pharmacists answer your medication & supplement questions — free.

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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.