Drug & supplement interaction

Guaiac Wood + Nitrofurantoin

Nitrofurantoin brand names: Macrodantin, Furadantin, Furatoin, Macrobid.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 27, 2026
The bottom line No known interaction

We found no known interaction between Guaiac Wood and Nitrofurantoin 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 Nitrofurantoin 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Guaiac Wood and Nitrofurantoin

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 Nitrofurantoin and Guaiac Wood 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.

Guaiac Wood safety at a glance

Guaiac Wood overall Use caution Mostly used externally or as a scent; little safety data for internal use.
Pregnancy Avoid Not enough safety information, so it is best avoided during pregnancy.
Breastfeeding Avoid No reliable safety data while breastfeeding, so avoid use.

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

Still wondering about combining Nitrofurantoin and Guaiac Wood? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Nitrofurantoin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Nitrofurantoin is filed under 3 classifications — antibiotic drugs, hepatotoxic drugs, oral drugs. Guaiac Wood has documented interactions with 1 drug class — the most serious being lithium (moderate) — and none of Nitrofurantoin’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

Guaiac Wood Does Interact With Other Medications

Guaiac Wood has 1 moderate known drug interaction in our database — Nitrofurantoin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 1 No known interaction 2,829 (incl. Nitrofurantoin)
Taking anything else?

Check Another of Your Medications Against Guaiac Wood

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

What to actually watch for

No Interaction Found — But Data Suggests Guaiac Wood and Nitrofurantoin 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.

  • Diarrhea reported in 5.7% of FDA reports for Nitrofurantoin Additional detail

    Guaiac Wood

    “Orally, high doses of guaiac wood can cause diarrhea, gatroenteritis, or intestinal colic (18).”

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

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Nitrofurantoin

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

Effects for Nitrofurantoin come from the ADVERSE REACTIONS section of its FDA label; effects for Guaiac Wood come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 22,743 voluntary FDA FAERS reports for Nitrofurantoin 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.

How to take them

Some Nitrofurantoin Products Have a Food Rule — Guaiac Wood Should Not Break It

At least one FDA label for a product containing Nitrofurantoin says to take it with food. If you take Guaiac Wood on an empty stomach out of habit, keep them separate — and take Nitrofurantoin with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Nitrofurantoin 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 Guaiac Wood or Nitrofurantoin

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

This page covers Guaiac Wood only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nitrofurantoin page lists 82 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Ashwagandha (moderate).

By severity: 4 major · 68 moderate · 10 minor.

From our pharmacist’s overview on the Nitrofurantoin page

“Nitrofurantoin (Macrobid, Macrodantin) treats urinary tract infections and can strain the liver on its own, which is why this interaction list deserves genuine care rather than a glance. Of the 82 ingredients on file, 38 can add their own liver stress on top of the drug's, and three of the four major-rated entries fall in that group, i…”

Reviewed by 2 · Jul 18, 2026

Open the Nitrofurantoin interaction page

How much people look this up

Where Guaiac Wood and Nitrofurantoin 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 Guaiac Wood
Steady interest

#1,390 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Nitrofurantoin
Top 25%

#464 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 Guaiac Wood reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Guaiac Wood and Nitrofurantoin 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 Guaiac Wood

What is Guaiac Wood?

  • Fragrance in perfumes and soaps
  • Aromatherapy and relaxation
  • Traditional anti-inflammatory remedy
  • Skin care products
  • Traditional joint and arthritis support

Guaiac wood is mainly valued for its sweet, smoky-rosy aroma and is used widely as a fragrance ingredient and in aromatherapy. There is very little high-quality human research supporting any health or medical benefit, so it should be thought of as a scent rather than a proven remedy. If you want to use it, talk to your pharmacist or doctor first, and avoid taking it by mouth.

Bulnesia sarmientoi · Zygophyllaceae · Wood and essential oil (also called guaiacwood oil) · Essential oil, aromatherapy blends, soaps and perfumes; sometimes wood chips or resin

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

Guaiac Wood: dosing

There is no established or standardized medical dose for guaiac wood. It is most often used in small amounts as a fragrance in finished products such as soaps, perfumes, or aromatherapy diffuser blends.If you choose to use a guaiac wood product, follow the directions on the label and dilute essential oils properly before applying them to skin.

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

Read the full Guaiac Wood monograph & all interactions
Medication

About Nitrofurantoin

What Is Nitrofurantoin Used For?

Brand names: Macrodantin, Furadantin, Furatoin, Macrobid

Nitrofurantoin treats urinary tract infections (UTIs) caused by specific susceptible bacteria. The capsule forms (including Macrodantin and nitrofurantoin macrocrystals capsules) are indicated for UTIs due to Escherichia coli, enterococci, Staphylococcus aureus, and certain strains of Klebsiella and Enterobacter species. Nitrofurantoin capsules (monohydrate/macrocrystals) are indicated only for acute uncomplicated UTIs (acute cystitis) caused by E. coli or Staphylococcus saprophyticus.

Nitrofurantoin oral suspension (Furadantin) is indicated for adults and children 1 month of age and older for UTIs caused by susceptible strains of E. coli, Enterococcus species, S. aureus, Klebsiella species, and Enterobacter species. No form of nitrofurantoin is approved for kidney infections (pyelonephritis) or infections in the tissue surrounding the kidneys (perinephric abscesses).

Most-Reported Side Effects for Nitrofurantoin

From FAERS, the FDA’s public side-effect reporting system (22,743 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Urinary tract infection 2,221 reports
Fatigue 1,839 reports
Nausea 1,827 reports
Headache 1,705 reports
Dyspnea 1,437 reports
See full Nitrofurantoin drug information
Keep checking

Other Drugs & Guaiac Wood

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

0Major
1Moderate
0Minor
2,828No known interaction
1 Moderate 2,828 No interaction
Moderate

1 interaction

No interaction 2,828 drugs checked — show the list

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

Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Guaiac Wood list.

See the full Guaiac Wood interactions page
See every supplement checked against Nitrofurantoin, ranked by severity
Evidence & sources

Guaiac Wood References

The 1 references that drive our Guaiac Wood 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.

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 Guaiac Wood and Nitrofurantoin Together: Common Questions

Is it safe to take Guaiac Wood with Nitrofurantoin?
We do not list a known interaction between Guaiac Wood and Nitrofurantoin. 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 Guaiac Wood and Nitrofurantoin 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.
Should I take Guaiac Wood and Nitrofurantoin at the same time of day?
At least one FDA label for a product containing Nitrofurantoin says to take it with food. If you take Guaiac Wood on an empty stomach out of habit, keep them separate and take Nitrofurantoin with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Nitrofurantoin products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Guaiac Wood and Nitrofurantoin combination checked?
Interactions in our licensed database are recorded against drug classes. Nitrofurantoin is filed under 3 classifications, and Guaiac Wood has documented interactions with 1 drug class — none of Nitrofurantoin'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 Guaiac Wood interact with any other medications?
Yes. Guaiac Wood has 1 documented drug interaction in our database — Nitrofurantoin 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 Nitrofurantoin interact with any supplements?
Yes. Nitrofurantoin has documented interactions with 82 supplements in our database — Guaiac Wood is not one of them. The Nitrofurantoin 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

Guaiac Wood monograph Uses, safety profile, and every drug interaction in one place Nitrofurantoin drug information The full plain-English guide to this medication Nitrofurantoin supplement interactions Every supplement checked against Nitrofurantoin, 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Nitrofurantoin and Guaiac Wood?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.