Herb & supplement monograph
Guaiac Wood Drug Interactions, Uses, Effectiveness, Safety & More
What is this page for?
First and foremost: how Guaiac Wood interacts with medications. The heart of this page is the interaction list — every drug Guaiac Wood is known to interact with, and how serious each one is.
But these pages have grown well beyond that into a full monograph — what Guaiac Wood is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy
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Guaiac Wood Drug Interactions: The Bottom Line
From the HelloPharmacist Editorial Team · Updated July 2026Based on the available evidence, the overall risk of a clinically significant Guaiac Wood drug interaction appears low for most people. Only a single interaction is known, rated moderate rather than major, and no other medications are affected.
Interactions deserving the most attention
The one combination that deserves real attention is lithium. Guaiac Wood is thought to act as a mild diuretic, and diuretics can slow the body's removal of lithium, which could raise lithium levels. Because lithium works within a narrow range and is closely monitored, even a modest change in its level can matter, so anyone taking lithium should discuss this supplement with their prescriber before using it.
What the rest of the list means
Check your medications against Guaiac Wood
It is worth keeping this concern in perspective. The lithium interaction is largely a prediction based on how Guaiac Wood may affect the way the kidneys handle the drug, not something confirmed by strong human studies. For people not taking lithium, Guaiac Wood has no other documented drug interactions in the current evidence.
Based on HelloPharmacist’s Guaiac Wood interaction data and reviewed under our editorial standards.
Interaction report
Drugs that interact with Guaiac Wood
1 medication has a known interaction with Guaiac Wood, graded by severity. Select any drug for the full evidence-based detail.
Don’t want to scroll the list? Just ask.
Tell us the medications you take and we’ll check each one against Guaiac Wood using our pharmacist-reviewed interaction data.
AI summaries are generated from our Guaiac Wood interaction data for education only — always confirm with your pharmacist. How we use AI
2,830 drugs
No drugs match “”.
Lithium Carbonate (prescription Drug)Eskalith, Lithium Carbonate
Moderate
Lithium
Theoretically, guaiac wood and resin might reduce excretion and increase levels of lithium.
Read the full Guaiac Wood + Lithium Carbonate (prescription Drug) interaction Lithium Carbonate (prescription Drug) drug page: uses, dosage & side effects
Read The List Like a Pharmacist
What Severity, Likelihood & Evidence Mean
Severity — How Serious It Can Be
- Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
- Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
- Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
- No known interaction. Checked against our sources with nothing documented — not the same as proven safety.
Likelihood — How Well It’s Documented
- Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
- Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
- Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
- Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Where This Data Comes From
- Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
- Each drug listed above links to the full report for that exact Guaiac Wood combination — clinical detail, likelihood, evidence level, and citations.
- Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture
The kinds of drugs Guaiac Wood affects
Every type of medication (drug category) Guaiac Wood is known to interact with. Open any category for the detail — or search your exact drug in the checker above.
All 1 drug category Guaiac Wood interacts with
Lithium
Lithium
Theoretically, guaiac wood and resin might reduce excretion and increase levels of lithium.
Guaiac wood and resin are thought to have diuretic properties. These diuretic properties might result in the reduced excretion and increased levels of lithium. The dose of lithium might need to be reduced.
Monograph
Guaiac Wood: Uses, Safety & Side Effects
The bottom line
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.
- Scientific name
- Bulnesia sarmientoi
- Family
- Zygophyllaceae
- Part used
- Wood and essential oil (also called guaiacwood oil)
- Common forms
- Essential oil, aromatherapy blends, soaps and perfumes; sometimes wood chips or resin
People commonly use it for
- Fragrance in perfumes and soaps
- Aromatherapy and relaxation
- Traditional anti-inflammatory remedy
- Skin care products
- Traditional joint and arthritis support
Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.
OverallUse caution
Mostly used externally or as a scent; little safety data for internal use.
PregnancyInsufficient reliable information
Insufficient reliable information available; avoid using.
Read the full pregnancy detailBreastfeedingInsufficient reliable information
Insufficient reliable information available; avoid using.
Read the full breastfeeding detailPregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Overview
Guaiac wood comes from trees in the Bulnesia and related groups that grow in the dry forests of South America, especially in the Gran Chaco region of Paraguay and Argentina. The wood is dense and oily, and it is steam-distilled to produce a thick, fragrant essential oil often called guaiacwood oil.
People have long valued guaiac wood for its warm, sweet, slightly smoky and rose-like scent. Today it is most commonly used as a fragrance ingredient in perfumes, soaps, and cosmetics, and in aromatherapy blends. It is sometimes confused with "guaiac" or "guaiacum" resin from Guaiacum species, which is a different plant used in older folk medicine.
How it works
The essential oil contains aromatic compounds such as guaiol and bulnesol, which give it its characteristic smell. These compounds have shown some activity in laboratory tests, including possible antimicrobial and antioxidant effects.
It is important to understand that most of this information comes from test-tube and animal studies, not from carefully designed human trials. Because of this, we cannot say with confidence how guaiac wood behaves in the human body or whether it produces any meaningful health effect.
Effectiveness
Does Guaiac Wood work?
Evidence overview · 2 uses evaluated
2 Insufficient evidence
How to read these evidence grades
Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.
1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.
For Guaiac Wood, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.
Also studied for 2 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Gout
Rating & evidence shown verbatim from Natural Medicines
Although there has been interested in using oral guaiac resin for preventing gout, there is insufficient reliable information about the clinical effects of guaiac resin for this purpose.
Insufficient Reliable Evidence To Rate Rheumatoid arthritis (RA)
Rating & evidence shown verbatim from Natural Medicines
Although there has been interest in using oral guaiac wood for RA, there is insufficient reliable information about the clinical effects of guaiac wood for this purpose.
Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.
Safety & precautions
Guaiac wood essential oil is generally used externally or for scent. As with other essential oils, it should not be swallowed unless directed by a qualified professional, and it should be diluted before applying to the skin. Undiluted essential oils can irritate the skin and eyes.
People with sensitive skin, allergies, or a history of reactions to fragrances should be cautious and consider a small patch test first. Pregnant or breastfeeding people should avoid guaiac wood because there is not enough safety information. Keep essential oils out of reach of children and pets.
Always check with your pharmacist or doctor before using guaiac wood, especially if you have a medical condition or take other medicines.
Side effects
When used as a diluted topical or aromatherapy product, side effects are not well documented but may include skin irritation, redness, or allergic reactions in sensitive people. Strong fragrances can also trigger headaches or breathing discomfort in some individuals.
Swallowing essential oils can cause nausea, vomiting, and other more serious effects, so internal use is not recommended without professional guidance. Stop using the product and seek medical advice if you notice a rash, swelling, or trouble breathing.
Guaiac Wood: Reported Adverse Effects
Documented safety reports on Guaiac Wood from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.
Reports by conditionDiarrhea Gastrointestinal
Orally, high doses of guaiac wood can cause diarrhea, gatroenteritis, or intestinal colic.
- Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
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.
Adverse-effects data: Natural Medicines, Therapeutic Research Center
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. Because reliable dosing information is lacking, check with a pharmacist or doctor before using it for any health purpose.
Pregnancy & Breastfeeding
Guaiac Wood & Pregnancy
Guaiac Wood & Breastfeeding
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
© 2026 Therapeutic Research Center
Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center
References & further reading
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.
- Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
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.
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Pharmacist Counseling Corner
Guaiac Wood: Common Questions
What is Guaiac Wood used for, and does it work?
People use Guaiac Wood for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Guaiac Wood interact with prescription medications?
Yes. We list 1 medication with a known interaction with Guaiac Wood. Use the checker above to see how Guaiac Wood interacts with a specific drug.
How are Guaiac Wood interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Guaiac Wood with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Guaiac Wood interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
What is Guaiac Wood used for?
It is used mainly as a fragrance in perfumes, soaps, and aromatherapy because of its warm, sweet, smoky-rosy scent. It also has folk uses, but there is little scientific evidence that it treats any health condition.
Is Guaiac Wood safe to take by mouth?
Guaiac Wood essential oil is not meant to be swallowed and can cause irritation or other harmful effects if taken internally. Use it only as a scent or as directed by a qualified professional.
Can I use Guaiac Wood while pregnant or breastfeeding?
No reliable safety information is available, so it is best to avoid Guaiac Wood during pregnancy and breastfeeding. Talk to your doctor or pharmacist before using any essential oil at these times.
Is Guaiac Wood the same as guaiacum or guaiac resin?
Not exactly. Guaiac Wood oil usually comes from Bulnesia trees and is prized for its scent, while "guaiacum" or guaiac resin comes from a different plant group and has separate traditional uses. The names are easily confused, so check the label and source.
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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