Cannabis & Cannabinoids · Terpenes · A woody-scented plant molecule found in cypress-pine and Bulnesia wood oils and in cannabis flower
Guaiol
2-[(3S,5R,8S)-3,8-dimethyl-1,2,3,4,5,6,7,8-octahydroazulen-5-yl]propan-2-ol ((-)-guaiol), C15H26O · also called Guaiol, (-)-guaiol, champacol, guaiac alcohol, champaca camphor, guai-1(5)-en-11-ol
Guaiol is a plant molecule (a sesquiterpene alcohol with fifteen carbon atoms). It is a main ingredient of some wood oils, such as those of Callitris cypress-pines and Bulnesia sarmientoi, and it is a smaller part of some cannabis flower. Almost all research is in dishes, insects and mouse tumour models. No trial has tested guaiol in people, and we found no human safety study.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Guaiol
Guaiol is a woody-scented plant molecule found in Callitris cypress-pine and Bulnesia wood oils, in Ferula plants, and in small amounts in some cannabis. Almost all research is in dishes, insects and mouse tumour models, and no trial has tested it in people. We found no human safety data. In our lab data it appears in 59 named strains, each from one commercial sample, with values that vary about 28-fold between the lowest and highest.
What it is
Guaiol is a sesquiterpene alcohol with the formula C15H26O (PubChem compound 227829). It is a 'guaiane' molecule, with a five-membered and a seven-membered carbon ring and one -OH group. The form studied is (-)-guaiol. Champacol and guaiac alcohol are other names for the same molecule.
Cannabis makes terpenes in the resin glands of the female flower. In a study of 21 varieties, guaiol was higher in CBD-dominant than in THC-dominant ones. How a plant makes guaiol was not found in the sources read.
Where you meet it
Guaiol is the largest component of the heartwood oil of Callitris neocaledonica (30.2%) and a leading one in C. sulcata (16.1%), two New Caledonian cypress-pine trees. Bulnesia sarmientoi essential oil was 48.29% guaiol in one screen. A Ferula ferulaeoides plant fraction was 37.0% guaiol. Guaiol is also described as the main sesquiterpene in the oil of Aloysia gratissima, and as a main component of a steam distillate of Callitris glaucophylla.
In cannabis it is one of four most abundant terpenes in medical flower from Brazil, and 0.17 to 2.60% of the steam-distilled flower oil of two South African cultivars. The USDA Duke database lists guaiol for American ginseng and St John's wort, but that is a secondary database and we did not read the original papers. A percentage in a plant oil does not tell you what the oil will do.
What the lab numbers show
Our data hold guaiol measurements for 59 named strains (68 values in all, because a few strains have more than one sample). Every value comes from one published study of 72 commercial medical cannabis samples analysed by gas chromatography with a flame ionisation detector at a lab in Las Cruces, New Mexico. Each value is a single batch of cured flower, not an average of many. The values are printed in the paper's supplement in a column headed '% dry wt', but their size looks like a fraction (for example, THC is printed as 0.263), so the unit is not independently verified. As printed, they run from 0.0000543 to 0.00154, with a middle value of about 0.000183. Do not compare these with percentages or mg/g from other datasets.
These numbers are real lab results from specific samples, not our own testing. The same strain name can have very different chemistry from sample to sample: Blue Dream has four values, from 0.000138 to 0.000917, a roughly 6.7-fold spread, and Lemon Skunk two values from 0.0000620 to 0.000189. Strain names are unreliable labels.
Examples, as printed and each a single sample unless stated: highest, Pineapple Skunk 0.00154, 8-Ball Kush 0.00144 and Jabberwocky (two samples, 0.00114 and 0.00142); lowest, Flo 0.0000543, Cookies and Cream 0.0000556 and Lohan 0.0000572. Among strains with a profile page here: White Widow 0.000805, Jack Herer 0.000569, Blue Dream 0.000138 to 0.000917 (four samples) and Chemdawg 0.0000992. The numbers measure the content of the flower. They say nothing about how a strain will feel or whether guaiol has any effect in people.
The popular claims
"Guaiol is a cancer fighter." In dishes and in mouse tumour models, pure guaiol killed lung cancer cells and changed immune signals. No person has been treated with it, most of the papers come from one research network, and the way it kills cells includes DNA damage. It is not a cancer treatment.
"Guaiol is in my strain, so it will feel a certain way." No study read links guaiol to any effect of cannabis. The cannabis studies we read only measured how much of it is there.
"Guaiol kills germs and bugs." It killed a parasite in dishes, and some insects in lab tests. The antifungal results are for whole wood oils, and the one antibacterial paper has no result in its abstract.
What the research shows
Human: none. We found no trial and no case report of guaiol on its own.
Animals and cells, lung cancer: in non-small cell lung cancer cells, pure (-)-guaiol lowered a DNA-repair protein (RAD51), blocked the mTOR growth signal and turned down PI3K/Akt. In mouse tumour models it reduced tumour growth, increased dendritic-cell and T-cell activity, reduced tumour-helping M2 macrophages through PPAR-gamma and IL-10/STAT3, and lowered PPARG and CD36 activity. A whole Bulnesia extract killed lung cancer cells at IC50 18.1 to 24.7 micrograms per mL and normal lung cells at 61.1.
Cells and insects, other uses: guaiol killed Leishmania amastigotes at an IC50 of 0.01 micrograms per mL in dishes. It inhibited aphids and killed moth larvae, houseflies and, as part of plant extracts, mosquito larvae. Heartwood oils that are about 16 to 30% guaiol stopped Candida krusei at low concentrations, but they are mixtures.
Rats: after a single oral dose of a Ferula extract, guaiol in the blood peaked at 0.5 hours and had a half-life of about 9 hours.
Regulatory status
We did not find a regulator document that sets rules for guaiol itself. PubChem's summary of company notifications lists no hazard class for the pure chemical (checked 2026-10-25), which is not an approval for any use. Rules on cannabis apply to cannabis and THC. We did not confirm whether guaiol appears on food-flavouring lists, and this page gives no legal advice.
At a glance
Traditional uses history, not proof
- Flavour and scent chemistry: guaiol is a named ingredient of some wood oils (this is chemistry, not a traditional use)
- Plants that contain it, such as Ferula ferulaeoides and Bulnesia sarmientoi, are described by research authors as used in traditional medicines; those are uses of the plants, and the claims were not checked against primary sources
Studied for research
- Lung cancer cells and tumours in animal models: dishes and mice, very low certainty, not a treatment
- Immune cells around lung tumours: mice, very low
- Leishmania parasites: dishes only, very low
- Insect and mosquito-larva killing: lab pest-control tests
- Skin fungi: whole wood oils in dishes, insufficient
- Bacteria: no result in the abstract, insufficient
- Cannabis flower extracts and colorectal cancer cells: whole extract, insufficient
Main compounds
- Guaiol, C15H26O (PubChem CID 227829)
- Other sesquiterpene alcohols found alongside it: bulnesol, alpha-, beta- and gamma-eudesmol, alpha-bisabolol
- Alpha-guaiene, beta-caryophyllene: named with guaiol in a Bulnesia extract study
- Related cannabis terpenes: beta-caryophyllene, humulene, bisabolol, nerolidol
Common forms
- Natural part of some cannabis flower and extracts
- Component of Callitris and Bulnesia wood oils and of Ferula plant fractions
- Pure compound in lab studies
Research links: PubChem: Guaiol · Guaiol and mTOR in lung cancer cells (PubMed) · Guaiol and M2 macrophages, PPAR-gamma (PubMed) · Guaiol against Leishmania in dishes (PubMed) · Cannabis chemotype markers incl. guaiol, Jin 2021 (PubMed) · Research Library · Genes & Biomarkers Library
What it is and its history
- Name
- Guaiol (also called (-)-guaiol, champacol or guaiac alcohol)
- Chemical name
- 2-[(3S,5R,8S)-3,8-dimethyl-1,2,3,4,5,6,7,8-octahydroazulen-5-yl]propan-2-ol
- Other names
- (-)-Guaiol; Champacol; Guaiac alcohol; Champaca camphor; Guai-1(5)-en-11-ol
- Common names
- Guaiol (English); Guaiol (Spanish)
- Formula
- C15H26O
- Molecular weight
- 222.37
- CAS number
- 489-86-1
- PubChem ID
- 227829
- Chemical class
- Sesquiterpenoid alcohol of the guaiane type (a 15-carbon plant molecule with a fused five- and seven-membered ring and one -OH group)
- How the plant makes it
- Not verified here. None of the sources read describes how the cannabis plant, or any plant, makes guaiol. Like other sesquiterpenes it is a 15-carbon terpene; the specific pathway was not read.
- Where it is found
- Cannabis flower: in a 21-variety study (Jin 2021) guaiol was higher in CBD-dominant than in THC-dominant varieties, and intermediate varieties resembled the CBD-dominant ones. In Brazilian medical flowers it was among the four most abundant terpenes (beta-caryophyllene, alpha-humulene, guaiol, alpha-bisabolol). In steam-distilled flower oil from two South African cultivars it was 0.17 to 2.60% of the oil.; Bulnesia sarmientoi (a tree whose extract was studied in lung cancer cells): guaiol was named among the main cytotoxic constituents; its essential oil was 48.29% guaiol in one screen. Whether this tree is the same as the wood sold as 'guaiac wood' was not checked in a source read.; Callitris neocaledonica heartwood oil, 30.2% guaiol; Callitris sulcata heartwood oil, 16.1% (New Caledonian cypress-pine trees).; Ferula ferulaeoides: guaiol was 37.0% of a dichloromethane fraction and was also the main compound in a rat blood-level study.; Aloysia gratissima essential oil: guaiol is described as its main sesquiterpene.; Callitris glaucophylla (Australian cypress pine): guaiol and citronellic acid were the main components of a steam distillate.; American ginseng and St John's wort: guaiol is listed in the USDA Duke database as copied into this site's data files (secondary database; original papers not read).
- Related or similar compounds
- Name: Bulnesol and alpha-/beta-/gamma-eudesmol; Note: Other sesquiterpene alcohols that appear alongside guaiol in Callitris and cannabis oils; they are different molecules.; Name: Alpha-bisabolol; Note: A different sesquiterpene alcohol also found in cannabis; it has its own page on this site.
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| Traditional Uygur medicine (as stated by a research paper) | A 2018 paper states that guaiol 'has been used for thousands of years as a traditional Uygur medicine' and is the main active component of Ferula ferulaeoides. This is the authors' statement; the underlying ethnobotanical sources were not read. | Yang 2018, J Chromatogr B (abstract) |
| Chinese medicinal plants (as stated by research papers) | The lung cancer papers say guaiol is found in many Chinese medicinal plants and traditional medicines. These are the authors' statements and were not checked against primary sources. | Yang 2018 and Yang 2023 abstracts |
| Bulnesia sarmientoi as a medicinal plant (as stated by the authors) | The authors say Bulnesia sarmientoi has long been used as a pain-relieving, wound-healing and anti-inflammatory plant. | Wang 2018, Molecules (abstract) |
| Name and origin | The names 'champacol' and 'guaiac alcohol' are PubChem synonyms. A claim that guaiol was first isolated from guaiacum wood is not verified here: no source for it was read. | PubChem synonyms list (CID 227829) |
History shows how a substance was used or discovered. It does not show that a product works or is safe today.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Guaiol PubChem 227829 | Sesquiterpene alcohol (guaiane) | Cannabis flower; Callitris and Bulnesia wood oils; Ferula See 'What the lab numbers show' on the Overview tab for measured cannabis values and their units. | Studied in lung cancer cells and mouse models, against Leishmania in dishes and as an insecticide. No human trial. 24 9 13 | Lab |
| Products made from guaiol by fungi | Oxidised guaiol derivatives | Lab-made, not plant-made | Five new compounds made from guaiol by three fungi were tested against bacteria; the abstract gives no result. 5 | Lab |
| Alpha-guaiene | Sesquiterpene hydrocarbon | Bulnesia sarmientoi extract | Named with guaiol and beta-caryophyllene as the main cause of the Bulnesia extract's cytotoxicity in lung cancer cells. 23 | Lab |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| mTOR signalling (mTORC1 and mTORC2) and autophagy | MTOR; AKT; EIF4EBP1; RPS6KB1 | In NSCLC cells (-)-guaiol lowered mTOR phosphorylation at S2481, reduced 4E-BP1 and p70 S6K signals and raised the LC3 II/I ratio (autophagy). An mTOR activator reversed the effects. 25 | Lab |
| DNA repair (RAD51) and apoptosis | RAD51 | Guaiol lowered RAD51 through autophagy, leading to double-strand DNA breaks and apoptosis; knocking down RAD51 made cells more sensitive. 24 | Lab |
| PI3K/Akt pathway | PI3K; AKT | Network prediction and cell tests tied guaiol's effect in lung adenocarcinoma cells to PI3K/Akt. 28 | Lab |
| Immunogenic cell death | Damage-associated molecular patterns (DAMPs) | Guaiol induced immunogenic cell death in vitro and increased dendritic-cell activation and T-cell infiltration in a mouse model. 27 | Animal research |
| M2 macrophage polarisation, IL-10/STAT3 | CD206; IL10; STAT3 | Guaiol reduced M2-like macrophages and, through IL-10/STAT3, EMT of lung cancer cells in co-culture; its tumour effect in mice needed macrophages. 3 | Animal research |
| PPAR-gamma signalling and fatty-acid oxidation | PPARG; CD36 | Guaiol suppressed M2 polarisation and lung cancer growth through PPAR-gamma, and lowered PPARG and CD36 gene activity in treated tumours. 29 30 | Animal research |
| Leishmania parasite structures | Kinetoplast, mitochondrial matrix, plasma membrane | Electron microscopy suggested guaiol damaged these structures in the parasite. 9 | Lab |
Absorption, metabolism and elimination
- Absorption
- No human data. In rats given a Ferula ferulaeoides chloroform extract by mouth (157.5 mg/kg, once), plasma guaiol peaked at 28.63 ± 6.82 ng/mL after 0.50 hours.
- Distribution
- Not described in the sources read.
- Metabolism
- Not described for animals or people. Three fungi oxidised guaiol in a lab to hydroxylated and ketone products (2007); this is fungal chemistry, not how the human body handles it.
- Elimination
- In the same rat study, half-life 9.18 ± 3.75 hours and mean residence time 9.07 ± 3.86 hours.
- Bioavailability
- Not established for any route. Nothing is known about blood levels from cannabis flower, vaping or oil.
5 very low certainty4 not enough evidence
What was looked at
The 9 benefits and uses checked for Guaiol, each with how strong the evidence is. Tap one to open it.
- Lung cancer cells in dishes and animal models (not a treatment)Very low certainty
- Immune cells around lung tumours (mice)Very low certainty
- Fatty-acid burning (PPARG) in lung cancer cells (mice and dishes)Very low certainty
- A plant extract that contains guaiol killed lung cancer cells in dishesNot enough evidence
- Leishmania parasites in dishesVery low certainty
- Insects and mosquito larvae (pest-control research)Very low certainty
- Skin fungi and yeasts in dishes (whole oils)Not enough evidence
- Bacteria (guaiol is described as antibacterial, but the abstract with the tests gives no results)Not enough evidence
- Cannabis flower extract and cancer cells (a whole extract, not guaiol)Not enough evidence
Lab markers tracked in the studies
Tumour size in mice (volume and weight)Lung cancer cell growth and survival in dishesAutophagy marker (LC3 II/I ratio) and mTOR signalsM2 macrophage marker (CD206)Leishmania parasite killing (IC50)Insect or larval death (LD50 / LC50)Fungal growth stopped (MIC)
What is Guaiol good for?
The uses people ask about and how strong the evidence is for each. For guaiol, all of it is from cells, animals or insects, and no trial has tested guaiol in people. The last rows are whole extracts or oils and cannot be credited to guaiol.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Lung cancer cells in dishes and animal models (not a treatment)
Very low certaintyIn dishes and in animal tumour models, pure (-)-guaiol slowed the growth of non-small cell lung cancer cells and made them die. No person has been given guaiol for lung cancer in a trial.
3 studiesPure (-)-guaiol, given in lab doses to cells or animals. Not a plant,…
Studies, doses and limits
Results
Across three papers, guaiol reduced lung cancer cell growth and caused cell death in dishes. The 2016 paper also reports that it reduced growth in vivo, in an animal model the abstract does not name. A 2018 paper reports it blocked both mTOR complexes and raised an autophagy marker. A 2022 computer-plus-cell paper pointed to the PI3K/Akt pathway.
Effect sizes as reported
No numbers (doses, percentage change, tumour size) are given in the three abstracts.
Why this rating
Everything is from cells or an unnamed animal model, from one research network, with no doses in the abstracts and no human data.
Form and dose studied
Pure (-)-guaiol, given in lab doses to cells or animals. Not a plant, not an essential oil and not cannabis flower.
Who was studied
Human lung cancer cell lines; an animal tumour model (species not named in the abstract).
Limits
Cell and animal studies mostly from one group. Doses used in animals cannot be compared with what a person would get from a plant. Results in dishes often fail to carry over to people.
Why researchers looked
Guaiol is a common plant scent molecule. A Chinese research group asked whether it could kill lung cancer cells and published a series of papers from 2016 on.
Proposed mechanism Lab
In these studies guaiol lowered a DNA-repair protein (RAD51) through autophagy, blocked the mTOR growth signal, and turned down PI3K/Akt. These findings come from cells and animal models, and the exact doses were not given in the abstracts.
A proposed mechanism does not show that the effect happens in people.
Do not use these results to treat cancer. Killing cells in a dish is not a treatment, and the way guaiol damages DNA and cell machinery is also a reason for caution.
Immune cells around lung tumours (mice)
Very low certaintyIn mice with lung tumours, guaiol seemed to wake the immune system up against the tumour and to reduce 'M2' macrophages, immune cells that help tumours grow. This is mouse and dish research only.
3 studiesPure (-)-guaiol, in lab doses.
Studies, doses and limits
Results
Mice treated with guaiol had smaller lung tumours, more dendritic-cell activation and more T-cell infiltration (2023). The tumour-shrinking effect needed macrophages to be present, and treated mice had fewer M2-like macrophages (2023). A 2025 paper reports lower CD206 and smaller tumours in mice and ties the effect to PPAR-gamma.
Effect sizes as reported
No numbers in the abstracts.
Why this rating
Mice and cultured cells only; abstracts give no numbers; same research network.
Form and dose studied
Pure (-)-guaiol, in lab doses.
Who was studied
Mice (strains not stated in abstracts) and mouse and human-derived cells in dishes.
Limits
Mouse immune systems differ from human ones. Doses and routes are not stated in the abstracts.
Why researchers looked
Tumours recruit immune cells that help them. Researchers asked whether guaiol changes that by acting on immune cells and not only on the tumour cells.
Proposed mechanism Lab
Guaiol triggered 'immunogenic' cell death in lung cancer cells, a kind of death that alerts dendritic cells and T-cells. It also lowered markers of M2 macrophages (CD206) through IL-10/STAT3 and PPAR-gamma signals.
A proposed mechanism does not show that the effect happens in people.
Do not use these results to treat cancer. Killing cells in a dish is not a treatment, and the way guaiol damages DNA and cell machinery is also a reason for caution.
Fatty-acid burning (PPARG) in lung cancer cells (mice and dishes)
Very low certaintyA 2026 paper reports that guaiol slowed lung cancer cells and xenograft tumours in mice by turning down a fat-burning gene pathway (PPARG).
2 studiesPure (-)-guaiol.
Studies, doses and limits
Results
In nude mice with human lung cancer xenografts, guaiol lowered PPARG and CD36 gene activity and the authors report reduced growth and invasion in cells and smaller xenografts.
Effect sizes as reported
No numbers in the abstract.
Why this rating
One group, one model, abstract gives no numbers; docking is a prediction.
Form and dose studied
Pure (-)-guaiol.
Who was studied
Human lung cancer cells; immune-deficient (nude) mice.
Limits
Predictions from computer docking are not evidence of effect in a body.
Why researchers looked
Computer searches predicted that guaiol binds several cancer-related proteins, and the team tested the PPARG pathway in cells and mice.
Proposed mechanism Lab
Docking suggested binding to SRC, PTGS2, GSK3B, PPARG, ESR1 and HSP90AA1, but only PPARG was tested further. Tumour PPARG and CD36 gene activity was lower in treated mice.
A proposed mechanism does not show that the effect happens in people.
Do not use these results to treat cancer. Killing cells in a dish is not a treatment, and the way guaiol damages DNA and cell machinery is also a reason for caution.
A plant extract that contains guaiol killed lung cancer cells in dishes
Not enough evidenceAn extract of Bulnesia sarmientoi wood, which contains guaiol, was toxic to two lung cancer cell lines and less toxic to normal lung cells. It cannot be credited to guaiol alone.
1 studiesSupercritical-fluid extract of Bulnesia sarmientoi, tested in dishes …
Studies, doses and limits
Results
The extract killed A549 and H661 lung cancer cells at IC50 values of 18.1 and 24.7 micrograms per mL and normal MRC-5 lung cells at 61.1 micrograms per mL, so it was less toxic to the normal cells but not harmless to them.
Effect sizes as reported
IC50 18.1 and 24.7 ug/mL (cancer cells) vs 61.1 ug/mL (normal cells).
Why this rating
A whole extract with ten constituents; guaiol was not tested alone in this paper.
Form and dose studied
Supercritical-fluid extract of Bulnesia sarmientoi, tested in dishes at microgram-per-mL levels. Not wood powder, not an oil from a shop.
Who was studied
Human lung cancer and normal lung cell lines.
Limits
Many compounds in the extract. Cells only.
Why researchers looked
Bulnesia sarmientoi has long been used as a pain-relieving, wound-healing and anti-inflammatory medicinal plant, according to the authors, and its bark extract had shown anti-cancer activity.
Traditional use
The authors say Bulnesia sarmientoi has long been used as a pain-relieving, wound-healing and anti-inflammatory plant. That is their statement, not a source we checked.
Proposed mechanism Lab
The extract caused necroptosis (a regulated form of cell death) and reduced cell migration and invasion in dishes. The authors state that alpha-guaiene, guaiol and beta-caryophyllene explain most of the toxicity, but the abstract gives no separate numbers.
A proposed mechanism does not show that the effect happens in people.
Do not use these results to treat cancer. Killing cells in a dish is not a treatment, and the way guaiol damages DNA and cell machinery is also a reason for caution. The extract also harmed normal lung cells at higher concentrations.
Leishmania parasites in dishes
Very low certaintyIn dishes, guaiol killed the parasite that causes cutaneous leishmaniasis at very low concentrations without harming mouse-type macrophages in the same test. It has not been tested in infected animals or people.
2 studiesPure guaiol and whole essential oils, in dishes.
Studies, doses and limits
Results
Guaiol killed intracellular Leishmania amazonensis amastigotes at an IC50 of 0.01 micrograms per mL. The Aloysia gratissima oil, of which guaiol is the main part, killed promastigotes at 25 and amastigotes at 0.16 micrograms per mL. Both were reported safe for macrophages up to 100 micrograms per mL. A separate screen of 16 oils found the Bulnesia sarmientoi oil (48.29% guaiol) among the more active (IC50 between 54.05 and 162.25 micrograms per mL), though the authors picked a different oil as the best candidate.
Effect sizes as reported
IC50 0.01 ug/mL (guaiol, amastigotes); oil 25 and 0.16 ug/mL.
Why this rating
Dishes only, one group for pure guaiol, no infected animal or human data.
Form and dose studied
Pure guaiol and whole essential oils, in dishes.
Who was studied
Leishmania amazonensis parasites and macrophages in dishes.
Limits
Dish results often fail in animals. The Bulnesia oil is a mixture, so its activity is not guaiol's alone.
Why researchers looked
Current leishmaniasis medicines are costly, toxic and face resistance, so labs screen plant oils and their main compounds.
Proposed mechanism Lab
Electron microscopy suggested guaiol damaged the parasite's kinetoplast, mitochondrial matrix and outer membrane.
A proposed mechanism does not show that the effect happens in people.
Not a treatment. Leishmaniasis is a serious infection that needs medical care.
Insects and mosquito larvae (pest-control research)
Very low certaintyGuaiol killed or deterred several insect species in lab tests, and plant extracts that contain guaiol killed mosquito larvae. This is pest-control research, not research on human health.
2 studiesPure guaiol and plant extracts used in insect tests.
Studies, doses and limits
Results
Guaiol isolated from Ferula ferulaeoides inhibited aphids at 70 mg/L, killed larvae by contact (LD50 0.07 mg per larva for Mythimna separata and 8.9 for Plutella xylostella) and by fumigation (LC50 3.5 and 16.9 microlitres per litre for M. separata larvae and adult houseflies). Callitris glaucophylla extracts killed mosquito larvae strongly for a plant product, but guaiol and citronellic acid, the main components of the steam distillate, were less active than the whole distillate, and synthetic insecticides were far more potent.
Effect sizes as reported
LD50 0.07 and 8.9 mg/larva; LC50 3.5 and 16.9 uL/L.
Why this rating
Lab insect tests only; nothing about human exposure or safety.
Form and dose studied
Pure guaiol and plant extracts used in insect tests.
Who was studied
Aphids, moth larvae, houseflies and mosquito larvae.
Limits
Does not show that guaiol repels or kills insects when used on skin or a home, and it says nothing about safety for people or pets.
Why researchers looked
Researchers look for plant chemicals that could serve as natural insecticides.
Proposed mechanism Lab
The abstracts do not describe how guaiol acts on insects.
A proposed mechanism does not show that the effect happens in people.
Do not use essential oils or plant extracts as insecticides on skin or in the home on the strength of this research.
Skin fungi and yeasts in dishes (whole oils)
Not enough evidenceWood oils that contain a lot of guaiol killed yeast and skin-fungus isolates in dishes at low concentrations. The effect cannot be credited to guaiol, because the oils contain many compounds.
1 studiesHeartwood essential oils.
Studies, doses and limits
Results
Callitris neocaledonica heartwood oil contained 30.2% guaiol and C. sulcata oil 16.1%. Against Candida krusei their MICs were 3.9 and 0.975 micrograms per mL. The authors describe these as similar to the reference drugs but the abstract's drug figures are given in mg/mL, so the comparison is unclear.
Effect sizes as reported
MIC 3.9 and 0.975 ug/mL (C. krusei, whole oils).
Why this rating
Whole oils tested; guaiol not tested alone; dishes only.
Form and dose studied
Heartwood essential oils.
Who was studied
Four skin-fungus species and six yeast species, clinical isolates.
Limits
Mixed oils with many sesquiterpenes. The authors' drug comparison is hard to interpret.
Why researchers looked
Fungal infections are a growing problem, and tree oils from New Caledonia were screened as sources of new antifungal compounds.
Proposed mechanism Lab
Not studied in the abstract.
A proposed mechanism does not show that the effect happens in people.
Not a treatment for fungal infections.
Bacteria (guaiol is described as antibacterial, but the abstract with the tests gives no results)
Not enough evidenceSeveral papers call guaiol an antibacterial compound. The one paper that tested guaiol-derived compounds against bacteria does not report the results in its abstract, so no activity can be stated here.
1 studiesGuaiol and fungal-made derivatives.
Studies, doses and limits
Results
In the 2007 paper, three fungi converted guaiol into five new oxidised compounds that were tested against bacterial strains. The abstract does not give the results.
Effect sizes as reported
No results in the abstract.
Why this rating
The abstract states no antibacterial result for guaiol.
Form and dose studied
Guaiol and fungal-made derivatives.
Who was studied
Bacterial strains in dishes.
Limits
Nothing can be concluded.
Why researchers looked
Guaiane-type compounds are known in the lung cancer papers as 'well known for antibacterial activities' (the authors' phrase).
Proposed mechanism Lab
Not described.
A proposed mechanism does not show that the effect happens in people.
Not a treatment for infections.
Cannabis flower extract and cancer cells (a whole extract, not guaiol)
Not enough evidenceEthanol extracts of six medical cannabis types, with guaiol among their main terpene-type compounds, were toxic to colorectal cancer cells in dishes. Because the extracts were mostly THC, nothing can be credited to guaiol.
1 studiesEthanol extracts of cannabis flowers from six genotypes, in dishes.
Studies, doses and limits
Results
All six extracts were highly toxic to Ht-29 colorectal cancer cells and showed selectivity over healthy colon cells. The extracts averaged 59.1% Δ9-THC and 1.84% CBD. Guaiol was one of about 11 main terpenes/terpenoids listed.
Effect sizes as reported
No guaiol-specific figures.
Why this rating
Whole extracts that were mostly THC; guaiol not tested alone.
Form and dose studied
Ethanol extracts of cannabis flowers from six genotypes, in dishes.
Who was studied
Human liver and colorectal cancer cell lines and healthy lung and intestinal cells.
Limits
Cannot separate the effect of guaiol from THC and other compounds.
Why researchers looked
Researchers asked whether the minor terpenes in cannabis, not just THC and CBD, change how an extract acts on cancer cells.
Proposed mechanism Lab
The abstract does not say which compound caused the effect.
A proposed mechanism does not show that the effect happens in people.
Not a cancer treatment. THC-rich extracts carry the usual THC risks (see the Safety tab).
Connections to the rest of health
How Guaiol connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Respiratory System | Biological association | Very low certainty | Studied for: Lung cancer cells in dishes and animal models (not a treatment) Studied for: Immune cells around lung tumours (mice) | 24 25 28 27 3 29 30 23 13 8 5 |
| Immune System | Biological association | Very low certainty | Studied for: Immune cells around lung tumours (mice) Studied for: Leishmania parasites in dishes | 27 3 29 9 1 |
| Integumentary System | Biological association | Not enough evidence | Studied for: Skin fungi and yeasts in dishes (whole oils) | 22 |
| Digestive System | Biological association | Not enough evidence | Studied for: Cannabis flower extract and cancer cells (a whole extract, not guaiol) | 10 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Lung cancer | Very low certainty | Cells and animal models only; not a treatment. Preparation or compound: Pure (-)-guaiol |
24 29 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Tumour size in mice (volume and weight) | Biological association | Very low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 29 24 27 30 |
| Lung cancer cell growth and survival in dishes | Biological association | Very low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 24 28 23 25 |
| Autophagy marker (LC3 II/I ratio) and mTOR signals | Biological association | Very low certainty | Measured in trials: mixed. A lab change is not the same as a health benefit. | 25 24 |
| M2 macrophage marker (CD206) | Biological association | Very low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 29 3 |
| Leishmania parasite killing (IC50) | Biological association | Very low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 9 1 |
| Insect or larval death (LD50 / LC50) | Biological association | Very low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 13 8 |
| Fungal growth stopped (MIC) | Biological association | Not enough evidence | Measured in trials: lowered. A lab change is not the same as a health benefit. | 22 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Guaiol | Biological association | Lab | Studied in lung cancer cells and mouse models, against Leishmania in dishes and as an insecticide. No human trial. Preparation or compound: Cannabis flower; Callitris and Bulnesia wood oils; Ferula |
24 9 13 |
| Products made from guaiol by fungi | Biological association | Lab | Five new compounds made from guaiol by three fungi were tested against bacteria; the abstract gives no result. Preparation or compound: Lab-made, not plant-made |
5 |
| Alpha-guaiene | Biological association | Lab | Named with guaiol and beta-caryophyllene as the main cause of the Bulnesia extract's cytotoxicity in lung cancer cells. Preparation or compound: Bulnesia sarmientoi extract |
23 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).
Evidence at a glance: what changed in 7 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Guaiol. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We searched PubMed and read the abstracts of about 28 sources, read PubChem for chemical identity and hazard notifications, and used our own cultivar lab-data file for the cannabis numbers. We say which sources we could not read.
Study library: every study we checked 30
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Andrade 2016 Essential oils: in vitro activity against Leishmania amazonensis, cytotoxicity and chemical composition. BMC Complement Altern Med · PMID 27825341 · DOI |
Laboratory research L. amazonensis; rat myoblast L6 cells |
L. amazonensis promastigotes and L6 cells in dishes | 16 essential oils, including Bulnesia sarmientoi oil (guaiol 48.29% by GC-MS) Essential oils IC50 at 24 h 24 h · vs Untreated cells |
Eight of sixteen oils were the most active, with IC50 54.05 to 162.25 µg/mL, including Bulnesia sarmientoi oil, whose main components were guaiol (48.29%) and 2-undecanone (19.49%). The authors name Ferula galbaniflua oil as the best candidate. Guaiol itself was not tested here. Eight of sixteen oils were the most active, with IC50 54.05 to 162.25 µg/mL, including Bulnesia sarmientoi oil, whose main components were guaiol (48.29%) and 2-undecanone (19.49%). The authors name Ferula galbaniflua oil as the best candidate. Guaiol itself was not tested here. Methods, limits and fundingOutcomes: IC50 against parasites, cytotoxicity (L6 cells), GC-MS composition Limitations: Whole oil only, not guaiol alone; the abstract does not say which oil was least toxic to the L6 cells apart from naming the Ferula oil as low in toxicity. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Bonn-Miller 2017 Labeling Accuracy of Cannabidiol Extracts Sold Online. JAMA · PMID 29114823 · DOI |
Cross sectional product testing |
CBD products sold online | Cannabidiol products Product |
The PubMed record has no results text (only the aim: to compare label ingredients with laboratory analysis). The figures were not read. The PubMed record has no results text (only the aim: to compare label ingredients with laboratory analysis). The figures were not read. Methods, limits and fundingOutcomes: Label vs lab content Limitations: Results not read for this page. Funding and conflicts: Not read Read: title only (no abstract results) |
| Cao 2023 (-)-Guaiol inhibit epithelial-mesenchymal transition in lung cancer via suppressing M2 macrophages mediated STAT3 signaling pathway. Heliyon · PMID 37809930 · DOI |
In vitro+animal mouse; mouse and human-derived cell lines (not specified in abstract) |
Mouse bone-marrow cells, lung cancer cells in co-culture, and mice with lung tumours | (-)-Guaiol, isolated compound Isolated compound Doses not given in the abstract · vs Macrophage-depleted mice; untreated |
In mice, (-)-Guaiol's suppression of lung tumour growth needed macrophages to be present; the effect was weaker when macrophages were depleted. Treated mice had fewer M2-like (tumour-helping) macrophages, but M1-like macrophages did not change. In co-culture, guaiol reduced M2 polarisation and the migration, invasion and EMT (a cell-shape change linked to spread) of lung cancer cells. The authors link this to IL-10 and STAT3 signalling. In mice, (-)-Guaiol's suppression of lung tumour growth needed macrophages to be present; the effect was weaker when macrophages were depleted. Treated mice had fewer M2-like (tumour-helping) macrophages, but M1-like macrophages did not change. In co-culture, guaiol reduced M2 polarisation and the migration, invasion and EMT (a cell-shape change linked to spread) of lung cancer cells. The authors link this to IL-10 and STAT3 signalling. Methods, limits and fundingOutcomes: M2-like macrophages, migration, invasion, EMT, IL-10, STAT3 Limitations: Mice and cells. No numbers in the abstract. Not shown in people. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Carvalho 2022 Chemical profiling of Cannabis varieties cultivated for medical purposes in southeastern Brazil. Forensic Sci Int · PMID 35462181 · DOI |
Chemical analysis Cannabis sativa (plant) |
35 35 cannabis plants grown by 15 licensed participants in Rio de Janeiro and São Paulo |
Dried cannabis flowers analysed for 5 cannabinoids and 19 terpenes Flower 10 to 24 week grow cycles |
The most abundant terpenes in the flowers were beta-caryophyllene, alpha-humulene, guaiol and alpha-bisabolol. CBD-rich varieties had significantly more beta-caryophyllene and alpha-humulene than THC-rich ones; the abstract does not give a guaiol comparison. The most abundant terpenes in the flowers were beta-caryophyllene, alpha-humulene, guaiol and alpha-bisabolol. CBD-rich varieties had significantly more beta-caryophyllene and alpha-humulene than THC-rich ones; the abstract does not give a guaiol comparison. Methods, limits and fundingOutcomes: Cannabinoid and terpene content Limitations: Plants grown in a few home/licensed settings; the abstract gives no guaiol amounts. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Choudhary 2007 Microbial transformation of (-)-guaiol and antibacterial activity of its transformed products. J Nat Prod · PMID 17385913 · DOI |
Laboratory research fungi; bacteria strains |
Three fungi used to chemically modify guaiol; bacteria strains | (-)-Guaiol and five new products made from it by fungi Isolated compound |
Three fungi (Rhizopus stolonifer, Cunninghamella elegans, Macrophomina phaseolina) converted (-)-guaiol into five new oxidised compounds. The compounds were tested against several bacterial strains. The abstract does not report the results of those tests. Three fungi (Rhizopus stolonifer, Cunninghamella elegans, Macrophomina phaseolina) converted (-)-guaiol into five new oxidised compounds. The compounds were tested against several bacterial strains. The abstract does not report the results of those tests. Methods, limits and fundingOutcomes: Structures of the products; antibacterial activity Limitations: The results of the antibacterial tests are not in the abstract, so no activity can be stated here. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Corsi 2020 Maternal cannabis use in pregnancy and child neurodevelopmental outcomes. Nat Med · PMID 32778828 · DOI |
Cohort study |
All live births in Ontario, Canada, 2007 to 2012 | Maternal cannabis use in pregnancy Cannabis · vs Unexposed pregnancies |
Autism spectrum disorder was diagnosed at 4.00 per 1,000 person-years in exposed children and 2.42 in unexposed (fully adjusted hazard ratio 1.51, 95% CI 1.17 to 1.96). The authors advise cautious interpretation because of possible residual confounding. Autism spectrum disorder was diagnosed at 4.00 per 1,000 person-years in exposed children and 2.42 in unexposed (fully adjusted hazard ratio 1.51, 95% CI 1.17 to 1.96). The authors advise cautious interpretation because of possible residual confounding. Methods, limits and fundingOutcomes: Autism diagnosis and other neurodevelopmental outcomes Limitations: Observational registry data; about cannabis use, not guaiol. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Di Forti 2019 The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study. Lancet Psychiatry · PMID 30902669 · DOI |
Case control |
2138 901 people with first-episode psychosis and 1,237 controls at 11 sites in Europe and Brazil |
Cannabis use patterns (daily use, high-potency THC 10% or more) Cannabis (smoked) Use pattern, not a dose · vs Never users |
Daily cannabis use was linked to higher odds of psychotic disorder than never use (adjusted odds ratio 3.2, 95% CI 2.2 to 4.1), and nearly five times higher odds for daily use of high-potency cannabis (4.8, 2.5 to 6.3). The authors estimated that, assuming causality, removing high-potency cannabis could prevent 12.2% of first-episode psychosis cases across the sites. Daily cannabis use was linked to higher odds of psychotic disorder than never use (adjusted odds ratio 3.2, 95% CI 2.2 to 4.1), and nearly five times higher odds for daily use of high-potency cannabis (4.8, 2.5 to 6.3). The authors estimated that, assuming causality, removing high-potency cannabis could prevent 12.2% of first-episode psychosis cases across the sites. Methods, limits and fundingOutcomes: Odds of psychotic disorder Limitations: Observational; association, not proof of cause. This concerns THC-containing cannabis, not guaiol. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Essam Abdel 2006 Efficacy of botanical extracts from Callitris glaucophylla, against Aedes aegypti and Culex annulirostris mosquitoes. Trop Biomed · PMID 17322820 |
Lab pest mosquito larvae |
4th-instar mosquito larvae (Aedes aegypti, Culex annulirostris) | Three Callitris glaucophylla extracts and the isolated components guaiol and citronellic acid Callitris glaucophylla (Australian cypress pine) LC50 0.23 to 38.95 mg/L (Culex) and 0.69 to 306.43 mg/L (Aedes) for the three extracts Standard WHO larval test · vs Two synthetic insecticides (lambda-cyhalothrin, fenitrothion) |
The three extracts killed mosquito larvae strongly for a plant product, but the synthetic insecticides were far more potent. The steam-distilled extract was fractionated; the main components were guaiol and citronellic acid. Their activity was lower than that of the whole distillate. The three extracts killed mosquito larvae strongly for a plant product, but the synthetic insecticides were far more potent. The steam-distilled extract was fractionated; the main components were guaiol and citronellic acid. Their activity was lower than that of the whole distillate. Methods, limits and fundingOutcomes: Larval LC50 Limitations: Mosquito larvae only. The abstract gives no separate numbers for guaiol. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Garcia 2018 The in vitro antileishmanial activity of essential oil from Aloysia gratissima and guaiol, its major sesquiterpene against Leishmania amazonensis. Parasitology · PMID 29352826 · DOI |
Laboratory research Leishmania amazonensis; macrophages in dishes |
Leishmania amazonensis parasites (promastigotes and intracellular amastigotes) and mouse-type macrophages in dishes | Aloysia gratissima essential oil and isolated guaiol Essential oil (leaves) IC50 25 µg/mL (oil, promastigotes), 0.16 µg/mL (oil, amastigotes), 0.01 µg/mL (guaiol, amastigotes) · vs Untreated parasites and cells |
The oil killed promastigotes (IC50 25 µg/mL) and intracellular amastigotes (0.16 µg/mL). Guaiol killed amastigotes at an IC50 of 0.01 µg/mL. Both were reported as safe for macrophages up to 100 µg/mL in the tests used. Neither increased nitric oxide in resting macrophages, and both lowered it in macrophages stimulated with LPS. Electron microscopy suggested direct damage to the parasite's kinetoplast, mitochondrion and membrane. The oil killed promastigotes (IC50 25 µg/mL) and intracellular amastigotes (0.16 µg/mL). Guaiol killed amastigotes at an IC50 of 0.01 µg/mL. Both were reported as safe for macrophages up to 100 µg/mL in the tests used. Neither increased nitric oxide in resting macrophages, and both lowered it in macrophages stimulated with LPS. Electron microscopy suggested direct damage to the parasite's kinetoplast, mitochondrion and membrane. Methods, limits and fundingOutcomes: Parasite killing (IC50), macrophage safety, nitric oxide Limitations: Dish study. Whether this is true in infected animals or people is unknown. The abstract says plant part only as 'essential oil'. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Janatová 2022 The chemical composition of ethanolic extracts from six genotypes of medical cannabis (Cannabis sativa L.) and their selective cytotoxic activity. Chem Biol Interact · PMID 34995571 · DOI |
Laboratory research human cell lines |
Human liver, colon and colorectal cancer cell lines and healthy lung and intestinal cells in dishes | Ethanol extracts of the flowers of six indoor-grown cannabis genotypes (average Δ9-THC 59.1%, CBD 1.84% of extract) Cannabis inflorescence (flower) extract Extract concentrations in µg/mL (for example 8.48 to 16.14 µg/mL for the most toxic extract) · vs Healthy cell lines (MRC-5, FHs 74 Int) |
More than 60 terpenes/terpenoids were identified. The major ones in most genotypes included limonene, linalool, alpha-terpineol, beta-caryophyllene, alpha-humulene, guaiol, gamma-eudesmol, beta-eudesmol and alpha-bisabolol. All extracts were highly toxic to Ht-29 colorectal cancer cells and showed selectivity compared with healthy FHs 74 Int colon cells. More than 60 terpenes/terpenoids were identified. The major ones in most genotypes included limonene, linalool, alpha-terpineol, beta-caryophyllene, alpha-humulene, guaiol, gamma-eudesmol, beta-eudesmol and alpha-bisabolol. All extracts were highly toxic to Ht-29 colorectal cancer cells and showed selectivity compared with healthy FHs 74 Int colon cells. Methods, limits and fundingOutcomes: Cannabinoid and terpene content; cytotoxicity and selectivity Limitations: Whole extracts that are about 59% THC, so the cell toxicity cannot be credited to guaiol. Dishes only. Guaiol was not tested alone. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Jin 2021 Identification of Chemotypic Markers in Three Chemotype Categories of Cannabis Using Secondary Metabolites Profiled in Inflorescences, Leaves, Stem Bark, and Roots. Front Plant Sci · PMID 34276749 · DOI |
Chemical analysis Cannabis sativa (plant) |
21 21 cannabis varieties (THC-dominant, intermediate, CBD-dominant) |
Cannabis plant parts analysed (flowers, leaves, stem bark, roots) Inflorescence, leaf, stem bark, root |
CBD-dominant varieties had higher amounts of (-)-guaiol (with beta-myrcene, beta- and alpha-eudesmol, alpha-bisabolol and alpha-pinene) than THC-dominant ones. Intermediate (THC about equal to CBD) varieties had more of these, including guaiol, than THC-dominant varieties and so resembled CBD-dominant ones. CBD-dominant varieties had higher amounts of (-)-guaiol (with beta-myrcene, beta- and alpha-eudesmol, alpha-bisabolol and alpha-pinene) than THC-dominant ones. Intermediate (THC about equal to CBD) varieties had more of these, including guaiol, than THC-dominant varieties and so resembled CBD-dominant ones. Methods, limits and fundingOutcomes: Content and ratio of cannabinoids, terpenoids, flavonoids, sterols, triterpenoids Limitations: Chemical profile of 21 varieties; no guaiol amounts in the abstract. Says nothing about effects. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Leung 2020 What is the prevalence and risk of cannabis use disorders among people who use cannabis? a systematic review and meta-analysis. Addict Behav · PMID 32485547 · DOI |
Systematic review |
21 studies of people who use cannabis | Cannabis use Cannabis |
Among people who used cannabis, 22% (18 to 26%) had a cannabis use disorder, 13% (8 to 18%) cannabis abuse and 13% (10 to 15%) cannabis dependence. Among young people who used regularly (weekly or daily), the risk of developing dependence rose to 33% (22 to 44%). Among people who used cannabis, 22% (18 to 26%) had a cannabis use disorder, 13% (8 to 18%) cannabis abuse and 13% (10 to 15%) cannabis dependence. Among young people who used regularly (weekly or daily), the risk of developing dependence rose to 33% (22 to 44%). Methods, limits and fundingOutcomes: Prevalence of cannabis use disorder, abuse and dependence Limitations: Observational studies of THC-containing cannabis; says nothing about guaiol alone. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Liu 2013 Guaiol--a naturally occurring insecticidal sesquiterpene. Nat Prod Commun · PMID 24354171 |
Lab pest insects |
Insects (aphids, armyworm and diamondback moth larvae, houseflies) | Guaiol isolated from the dichloromethane fraction of Ferula ferulaeoides Ferula ferulaeoides (plant fraction) 70 mg/L (aphids); LD50 0.07 and 8.9 mg/larva; LC50 3.5 and 16.9 µL/L |
Guaiol made up 37.0% of the plant fraction. It significantly inhibited aphids at 70 mg/L. Contact LD50 values were 0.07 mg per larva (4th-instar Mythimna separata) and 8.9 mg per larva (3rd-instar Plutella xylostella). Fumigation LC50 values were 3.5 µL/L (M. separata larvae) and 16.9 µL/L (adult Musca domestica). Guaiol made up 37.0% of the plant fraction. It significantly inhibited aphids at 70 mg/L. Contact LD50 values were 0.07 mg per larva (4th-instar Mythimna separata) and 8.9 mg per larva (3rd-instar Plutella xylostella). Fumigation LC50 values were 3.5 µL/L (M. separata larvae) and 16.9 µL/L (adult Musca domestica). Methods, limits and fundingOutcomes: Insect inhibition and mortality Limitations: Insect tests. Says nothing about safety or effects in people or other animals. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Odieka 2026 Chemical Characterization and Biological Potential of the Essential Oils from the Flowers of Two Cannabis sativa L. Cultivars from Komga, South Africa. Molecules · PMID 42280118 · DOI |
Chemical analysis+in vitro Cannabis sativa (plant) |
Fresh and dried flower essential oils from the cultivars Lifter and Cherrywine | Hydro-distilled flower essential oil Flower Guaiol 0.17 to 2.60% of the oil |
Guaiol made up 0.17 to 2.60% of the oils, among 18 main constituents shared by the two cultivars (caryophyllene was highest at 10.71 to 19.96%). The antioxidant activity of the oils was moderate to low (IC50 69.50 µg/mL for fresh Lifter flower oil; the other oils stayed below 50% inhibition). Guaiol made up 0.17 to 2.60% of the oils, among 18 main constituents shared by the two cultivars (caryophyllene was highest at 10.71 to 19.96%). The antioxidant activity of the oils was moderate to low (IC50 69.50 µg/mL for fresh Lifter flower oil; the other oils stayed below 50% inhibition). Methods, limits and fundingOutcomes: GC-MS composition; DPPH antioxidant and anti-inflammatory tests; docking Limitations: Steam-distilled oil, a different measure from dried-flower content. Whole oils, so no activity can be credited to guaiol. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Richins 2018 Accumulation of bioactive metabolites in cultivated medical Cannabis. PLoS One · PMID 30036388 · DOI |
Chemical analysis Cannabis sativa (plant) |
72 72 commercial medical cannabis samples from licensed commercial producers, analysed by a lab in Las Cruces, New Mexico (supplementary Table S1) |
Cured cannabis flower analysed by GC-FID for cannabinoids and terpenoids Flower |
The paper develops a simple extraction and analysis method for cannabinoids and terpenoids, finds that terpenoid composition varies by accession and clusters strains into types, and argues terpenoids should be reported with cannabinoids. The guaiol values on this page come from its supplementary table S1, as recorded in our lab-data file (read 2026-10-22), not from the abstract. The paper develops a simple extraction and analysis method for cannabinoids and terpenoids, finds that terpenoid composition varies by accession and clusters strains into types, and argues terpenoids should be reported with cannabinoids. The guaiol values on this page come from its supplementary table S1, as recorded in our lab-data file (read 2026-10-22), not from the abstract. Methods, limits and fundingOutcomes: Cannabinoid and terpenoid content by strain name Limitations: Each strain name is one batch of one commercial sample. The unit is printed as '% dry wt' but the magnitudes look like mass fractions, so the unit is not independently verified. The authors' competing-interest statement ties the analysis to a commercial lab. Funding and conflicts: Competing-interest statement mentions Rio Grande Analytics (the analysis lab); see the paper. Read: abstract |
| Rogeberg 2016 The effects of cannabis intoxication on motor vehicle collision revisited and revised. Addiction · PMID 26878835 · DOI |
Meta-analysis |
21 observational studies (28 estimates), 13 countries | Acute cannabis intoxication Cannabis · vs Unimpaired drivers |
Cannabis-impaired driving was associated with a statistically significant risk increase of low-to-moderate size (random-effects odds ratio 1.36, 95% CI 1.15 to 1.61; meta-regression 1.22, 1.1 to 1.36). Cannabis-impaired driving was associated with a statistically significant risk increase of low-to-moderate size (random-effects odds ratio 1.36, 95% CI 1.15 to 1.61; meta-regression 1.22, 1.1 to 1.36). Methods, limits and fundingOutcomes: Crash risk Limitations: Observational and varied in quality; about THC-containing cannabis, not guaiol. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Sorensen 2017 Cannabinoid Hyperemesis Syndrome: Diagnosis, Pathophysiology, and Treatment-a Systematic Review. J Med Toxicol · PMID 28000146 · DOI |
Systematic review |
183 included articles and case reports | Regular cannabis use Cannabis |
Cannabinoid hyperemesis syndrome is cyclic nausea and vomiting after regular cannabis use. All cases had regular use and cyclic vomiting; 96.8% improved after stopping; 92.3% reported compulsive hot baths with relief. The cause is unclear, and stopping cannabis appears to be the best treatment. Cannabinoid hyperemesis syndrome is cyclic nausea and vomiting after regular cannabis use. All cases had regular use and cyclic vomiting; 96.8% improved after stopping; 92.3% reported compulsive hot baths with relief. The cause is unclear, and stopping cannabis appears to be the best treatment. Methods, limits and fundingOutcomes: Diagnostic features, pathophysiology, treatment Limitations: Case reports and small studies; concerns cannabis with THC, not guaiol alone. Funding and conflicts: Not stated in the abstract. Read: abstract |
| US Department of Agriculture (Duke database) 2026 USDA Phytochemical and Ethnobotanical Databases (Dr. Duke's), as held in this site's own data files for American ginseng and St John's wort Local data files read 2026-10-25 · Source |
Database n/a |
n/a | n/a |
The data files list guaiol among reported chemicals of American ginseng (with a number from a cited paper) and, with no value, among the reported chemicals of St John's wort. Guaiol is listed for American ginseng and St John's wort. Methods, limits and fundingOutcomes: Whether guaiol is listed for these plants Limitations: Secondary database. The original papers behind the entries were not read, so the amounts are not repeated here. Funding and conflicts: n/a Read: database file |
| US National Library of Medicine (PubChem) 2026 PubChem GHS classification summary for Guaiol (CID 227829) PubChem REST API (retrieved 2026-10-25) · Source |
Authoritative guidance n/a |
n/a | n/a |
PubChem reports that the chemical does not meet GHS hazard criteria in 100% (234 of 234) of the reports, from 1 notification to the ECHA C&L Inventory; no hazard statement codes were notified. PubChem reports that the chemical does not meet GHS hazard criteria in 100% (234 of 234) of the reports, from 1 notification to the ECHA C&L Inventory; no hazard statement codes were notified. Methods, limits and fundingOutcomes: Chemical identity / hazard notifications Limitations: A classification summary for the pure chemical from company notifications. No hazard notified is not proof of safety, and it does not cover inhaling, heating or use inside cannabis. Funding and conflicts: n/a Read: full-text |
| US National Library of Medicine (PubChem) 2026 PubChem: Guaiol (CID 227829) PubChem REST API (retrieved 2026-10-25) · Source |
Authoritative guidance n/a |
n/a | n/a |
CID 227829: C15H26O, molecular weight 222.37, IUPAC name 2-[(3S,5R,8S)-3,8-dimethyl-1,2,3,4,5,6,7,8-octahydroazulen-5-yl]propan-2-ol, InChIKey TWVJWDMOZJXUID-SDDRHHMPSA-N. Synonyms include (-)-guaiol, champacol, guaiac alcohol, champaca camphor, guai-1(5)-en-11-ol and CAS 489-86-1. CID 227829: C15H26O, molecular weight 222.37, IUPAC name 2-[(3S,5R,8S)-3,8-dimethyl-1,2,3,4,5,6,7,8-octahydroazulen-5-yl]propan-2-ol, InChIKey TWVJWDMOZJXUID-SDDRHHMPSA-N. Synonyms include (-)-guaiol, champacol, guaiac alcohol, champaca camphor, guai-1(5)-en-11-ol and CAS 489-86-1. Methods, limits and fundingOutcomes: Chemical identity / hazard notifications Limitations: A database record: identifies the molecule and says nothing about effects. Funding and conflicts: n/a Read: full-text |
| Vandrey 2015 Cannabinoid Dose and Label Accuracy in Edible Medical Cannabis Products. JAMA · PMID 26103034 · DOI |
Cross sectional product testing |
Edible medical cannabis products | Cannabis edibles Product |
The PubMed record has no abstract. The title shows that label accuracy of edibles was tested; the findings were not read. The PubMed record has no abstract. The title shows that label accuracy of edibles was tested; the findings were not read. Methods, limits and fundingOutcomes: Label vs lab content Limitations: Results not read for this page. Funding and conflicts: Not read Read: title only (no abstract) |
| Waikedre 2012 Antifungal Activity of the Essential Oils of Callitris neocaledonica and C. sulcata Heartwood (Cupressaceae). Chem Biodivers · PMID 22422531 · DOI |
Laboratory research fungi and yeasts in dishes |
Clinical isolates of four skin-fungus species and six yeasts in dishes | Heartwood essential oils of C. neocaledonica (guaiol 30.2%) and C. sulcata (guaiol 16.1%) Heartwood MICs 3.9 and 0.975 µg/mL against Candida krusei · vs Itraconazole and fluconazole |
Guaiol was the largest component of C. neocaledonica oil (30.2%) and the largest named in C. sulcata oil (16.1%). The best antifungal results were against Candida krusei (MICs 3.9 and 0.975 µg/mL). C. neocaledonica oil scavenged more DPPH radical than C. sulcata oil (93.3% vs 32.2% at 250 µg/mL). Guaiol was the largest component of C. neocaledonica oil (30.2%) and the largest named in C. sulcata oil (16.1%). The best antifungal results were against Candida krusei (MICs 3.9 and 0.975 µg/mL). C. neocaledonica oil scavenged more DPPH radical than C. sulcata oil (93.3% vs 32.2% at 250 µg/mL). Methods, limits and fundingOutcomes: Minimum inhibitory concentration; DPPH radical scavenging Limitations: Whole oils with many components; the effect cannot be credited to guaiol. The abstract's comparison with reference drugs mixes units (µg/mL and mg/mL). Dishes only. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Wang 2018 Bulnesia sarmientoi Supercritical Fluid Extract Exhibits Necroptotic Effects and Anti-Metastatic Activity on Lung Cancer Cells. Molecules · PMID 30551590 · DOI |
Laboratory research human cell lines |
Human lung cancer cell lines A549 and H661; normal lung cells MRC-5 | Bulnesia sarmientoi supercritical fluid extract (BSE), a whole-plant extract Bulnesia sarmientoi (wood extract) IC50 18.1 µg/mL (A549) and 24.7 µg/mL (H661); 61.1 µg/mL in normal MRC-5 cells 72 h · vs Untreated cells |
The extract was toxic to lung cancer cells (IC50 18.1 and 24.7 µg/mL) and less toxic to normal MRC-5 cells (IC50 61.1 µg/mL). It arrested cells in S and G2/M phases and caused a kind of cell death (necroptosis) that Nec-1 reduced. It also reduced migration and invasion. GC-MS found ten constituents; the authors state that alpha-guaiene, (-)-guaiol and beta-caryophyllene account for most of the cytotoxic activity against the two lines. The extract was toxic to lung cancer cells (IC50 18.1 and 24.7 µg/mL) and less toxic to normal MRC-5 cells (IC50 61.1 µg/mL). It arrested cells in S and G2/M phases and caused a kind of cell death (necroptosis) that Nec-1 reduced. It also reduced migration and invasion. GC-MS found ten constituents; the authors state that alpha-guaiene, (-)-guaiol and beta-caryophyllene account for most of the cytotoxic activity against the two lines. Methods, limits and fundingOutcomes: Cell viability (MTT), cell cycle, necroptosis, migration, invasion, extract composition Limitations: A whole extract with ten constituents, so effects cannot be credited to guaiol alone. Cells only. The abstract does not say the wood part or the guaiol share. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Yang 2016 (-)-Guaiol regulates RAD51 stability via autophagy to induce cell apoptosis in non-small cell lung cancer. Oncotarget · PMID 27566579 · DOI |
In vitro+animal human cells; animal model (species not named in abstract) |
Human non-small cell lung cancer (NSCLC) cells in dishes and tumours in animals | (-)-Guaiol, isolated compound Isolated compound Doses not given in the abstract |
(-)-Guaiol significantly inhibited growth of NSCLC cells in dishes and in vivo. A screen pointed to RAD51, a DNA-repair protein, as a likely target. The authors report that guaiol acts through autophagy to lower RAD51, leading to double-strand DNA breaks and cell death (apoptosis). Lowering RAD51 further increased the cells' sensitivity to guaiol in dishes and in vivo. (-)-Guaiol significantly inhibited growth of NSCLC cells in dishes and in vivo. A screen pointed to RAD51, a DNA-repair protein, as a likely target. The authors report that guaiol acts through autophagy to lower RAD51, leading to double-strand DNA breaks and cell death (apoptosis). Lowering RAD51 further increased the cells' sensitivity to guaiol in dishes and in vivo. Methods, limits and fundingOutcomes: Cell growth, RAD51 level, apoptosis, tumour growth Limitations: Cells and an animal model only; the abstract does not name the animal, the doses or the numbers. Tells us nothing about use in people. Damage to DNA is how it kills cells, which is also a reason for caution. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Yang 2018 (-)-Guaiol regulates autophagic cell death depending on mTOR signaling in NSCLC. Cancer Biol Ther · PMID 29611762 · DOI |
Laboratory research human cells |
Human NSCLC cells in dishes | (-)-Guaiol, isolated compound Isolated compound Doses not given in the abstract · vs Untreated cells; an mTOR activator (MHY1485) used to test the pathway |
In NSCLC cells (-)-Guaiol blocked mTORC2-AKT signalling by lowering mTOR phosphorylation at serine 2481, raised the LC3 II/I ratio (a sign of autophagy), and reduced signals from mTORC1 targets (4E-BP1, p70 S6K). The mTOR activator MHY1485 reversed these effects. Cell survival, colony-formation and flow-cytometry tests led the authors to conclude that guaiol triggered autophagic cell death through both mTOR complexes. In NSCLC cells (-)-Guaiol blocked mTORC2-AKT signalling by lowering mTOR phosphorylation at serine 2481, raised the LC3 II/I ratio (a sign of autophagy), and reduced signals from mTORC1 targets (4E-BP1, p70 S6K). The mTOR activator MHY1485 reversed these effects. Cell survival, colony-formation and flow-cytometry tests led the authors to conclude that guaiol triggered autophagic cell death through both mTOR complexes. Methods, limits and fundingOutcomes: mTOR signalling, LC3 II/I ratio (autophagy), cell survival, colony formation Limitations: Cell experiments only. The abstract gives no doses or numbers. The authors' remark that it could replace rapamycin is a hope, not a result. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Yang 2018 Determination and pharmacokinetic study of guaiol in rat plasma by gas chromatography-mass spectrometry with selected ion monitoring. J Chromatogr B Analyt Technol Biomed Life Sci · PMID 29627637 · DOI |
Animal pharmacokinetics rat |
Rats | Chloroform extract of Ferula ferulaeoides, by mouth, single dose (157.5 mg/kg) Ferula ferulaeoides (plant extract) 157.5 mg/kg of extract, once, by mouth Single dose |
After a single oral dose of the extract, guaiol in rat plasma reached a peak of 28.63 ± 6.82 ng/mL at 0.50 h, with a half-life of 9.18 ± 3.75 h and a mean residence time of 9.07 ± 3.86 h. The paper's main aim was to build a sensitive test (range 1 to 200 ng/mL). After a single oral dose of the extract, guaiol in rat plasma reached a peak of 28.63 ± 6.82 ng/mL at 0.50 h, with a half-life of 9.18 ± 3.75 h and a mean residence time of 9.07 ± 3.86 h. The paper's main aim was to build a sensitive test (range 1 to 200 ng/mL). Methods, limits and fundingOutcomes: Guaiol blood levels over time Limitations: Rats given a plant extract, not pure guaiol and not people. Says nothing about absorption from cannabis. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Yang 2023 (-)-Guaiol triggers immunogenic cell death and inhibits tumor growth in non-small cell lung cancer. Mol Cell Biochem · PMID 36441354 · DOI |
In vitro+animal human cells; animal model (not named in abstract) |
NSCLC cells in dishes; mouse tumour model | (-)-Guaiol, isolated compound Isolated compound Doses not given in the abstract · vs Untreated/vaccination controls |
In dishes (-)-Guaiol induced immunogenic cell death (a kind of cell death that alerts the immune system). In animals it suppressed tumour growth, increased dendritic-cell activation and increased T-cell infiltration. Vaccination experiments suggested that cells treated this way could suppress tumour growth. Blocking apoptosis or autophagy partly reversed the release of the danger signals. In dishes (-)-Guaiol induced immunogenic cell death (a kind of cell death that alerts the immune system). In animals it suppressed tumour growth, increased dendritic-cell activation and increased T-cell infiltration. Vaccination experiments suggested that cells treated this way could suppress tumour growth. Blocking apoptosis or autophagy partly reversed the release of the danger signals. Methods, limits and fundingOutcomes: Immunogenic cell death markers, tumour growth, dendritic cell activation, T-cell infiltration Limitations: Cells and animals; the abstract does not give numbers or doses. Not tested in people. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Zeng 2022 Integrating Network Pharmacology, Molecular Docking, and Experimental Validation to Investigate the Mechanism of (-)-Guaiol Against Lung Adenocarcinoma. Med Sci Monit · PMID 35871777 · DOI |
In vitro+computational human cells; computer models |
Lung adenocarcinoma (LUAD) cell lines; patient gene data from a public database for the computer part | (-)-Guaiol, isolated compound Isolated compound Doses not given in the abstract · vs Untreated cells |
Computer analysis of public patient gene data predicted 480 drug-target genes and 23 hub genes, with the PI3K/Akt pathway most prominent. In cell tests (-)-Guaiol inhibited LUAD cell growth and induced apoptosis, and the authors report that PI3K/Akt was involved, in line with the prediction. Computer analysis of public patient gene data predicted 480 drug-target genes and 23 hub genes, with the PI3K/Akt pathway most prominent. In cell tests (-)-Guaiol inhibited LUAD cell growth and induced apoptosis, and the authors report that PI3K/Akt was involved, in line with the prediction. Methods, limits and fundingOutcomes: Predicted targets, cell growth (CCK-8), cell death, apoptosis, western blots Limitations: Predictions plus cell tests. The computer part does not show what happens in a body. No animal or human test in this paper. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Zhao 2025 (-)-Guaiol Downregulates M2 Tumor-Associated Macrophage Polarization Through PPAR-γ Signaling to Suppress Lung Cancer. Biol Proced Online · PMID 41350836 · DOI |
In vitro+animal mouse |
Mouse bone-marrow macrophages, Lewis lung carcinoma (LLC) cells, tumour-bearing mice | (-)-Guaiol, isolated compound Isolated compound Doses not given in the abstract · vs PPAR-γ agonists and inhibitors used to test the pathway |
(-)-Guaiol markedly lowered CD206, a marker of M2-polarised macrophages. It reduced the growth, invasion and spread of LLC cells grown with M2 macrophages. In mice it decreased tumour volume and weight and CD206 expression. Integrated tests indicated the effect worked mainly by suppressing the PPAR-γ signalling pathway. (-)-Guaiol markedly lowered CD206, a marker of M2-polarised macrophages. It reduced the growth, invasion and spread of LLC cells grown with M2 macrophages. In mice it decreased tumour volume and weight and CD206 expression. Integrated tests indicated the effect worked mainly by suppressing the PPAR-γ signalling pathway. Methods, limits and fundingOutcomes: CD206 (M2 marker), proliferation, invasion, tumour volume and weight Limitations: Mouse cells and mice. The abstract gives no numbers or doses. Not tested in people. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Zhao 2026 (-)-Guaiol inhibits lung cancer via PPARG-dependent fatty acid oxidation. Neoplasma · PMID 41866994 · DOI |
In vitro+animal+computational human cells; nude mice |
Lung cancer cells and nude mice with xenograft tumours; computer target prediction | (-)-Guaiol, isolated compound Isolated compound Doses not given in the abstract · vs Control group |
Computer searches found 153 predicted guaiol targets and 91 shared with lung cancer; docking suggested good binding to SRC, PTGS2, GSK3B, PPARG, ESR1 and HSP90AA1. In treated mice, PPARG and CD36 gene activity was lower in the tumours. The authors report that guaiol inhibited lung cancer cell growth and invasion and xenograft growth in mice by turning down the PPARG pathway (fatty-acid burning). Computer searches found 153 predicted guaiol targets and 91 shared with lung cancer; docking suggested good binding to SRC, PTGS2, GSK3B, PPARG, ESR1 and HSP90AA1. In treated mice, PPARG and CD36 gene activity was lower in the tumours. The authors report that guaiol inhibited lung cancer cell growth and invasion and xenograft growth in mice by turning down the PPARG pathway (fatty-acid burning). Methods, limits and fundingOutcomes: Predicted targets, docking, mRNA sequencing, cell proliferation and invasion, xenograft growth Limitations: Predictions, cells and mice from one group. No dose or tumour numbers in the abstract. Not in people. Funding and conflicts: Not stated in the abstract. Read: abstract |
What we do not know yet
- What the evidence supports: everything is very-low or insufficient certainty, from cells, animals or insects.
- No human trial or case report of guaiol on its own, and no human safety study.
- Most of the cancer work comes from one research network; independent repeats were not found.
- The animal doses and cell concentrations cannot be compared with the amount in cannabis flower or a wood oil.
- No data on how people absorb or break down guaiol, or on interactions with medicines.
- We did not read LiverTox, EFSA or FDA documents about guaiol.
How new research is added
New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it changes any evidence rating or safety wording. New publications can change what this page says.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 7
Tumour size in mice (volume and weight)
Lowered in trials
How big the tumour grows in a mouse.
Very low certaintyResults and what it means
Why it was measured
The standard first test of whether a compound slows tumour growth before any human study.
Statistical vs. clinical meaning
Consistent direction across animal studies, but same research network and no numbers.
Safety implication
Tumour shrinkage in mice does not predict what happens in people.
| Study | Result | People | Product |
|---|---|---|---|
| 29 | Guaiol decreased tumour volume and weight in mice (numbers not in abstract). | Mice with Lewis lung carcinoma | (-)-Guaiol |
| 24 | Guaiol inhibited NSCLC cell growth in vivo (numbers not in abstract). | Animal model, species not stated | (-)-Guaiol |
| 27 | Guaiol suppressed tumour growth in vivo (numbers not in abstract). | Mouse tumour model | (-)-Guaiol |
Lung cancer cell growth and survival in dishes
Lowered in trials
How many cancer cells survive, form colonies or divide after being treated.
Very low certaintyResults and what it means
Why it was measured
Shows whether a compound is toxic to cancer cells in a lab.
Statistical vs. clinical meaning
Cells in dishes only; the extract result is not about guaiol alone.
Safety implication
Toxicity to cells in a dish can also mean toxicity to normal cells at higher levels.
| Study | Result | People | Product |
|---|---|---|---|
| 24 | Significant inhibition of cell growth in NSCLC cells. | Human NSCLC cells | (-)-Guaiol |
| 28 | Inhibited LUAD cell growth and induced apoptosis. | Human lung adenocarcinoma cells | (-)-Guaiol |
| 23 | Whole Bulnesia extract: IC50 18.1 (A549) and 24.7 (H661) ug/mL; normal MRC-5 cells 61.1 ug/mL. | Human lung cell lines | Bulnesia sarmientoi supercritical fluid extract |
Autophagy marker (LC3 II/I ratio) and mTOR signals
Mixed results in trials
Proteins that show whether a cell is digesting its own parts (autophagy) and whether the mTOR growth signal is on.
Very low certaintyResults and what it means
Why it was measured
These signals tell researchers how a compound is killing cells.
Statistical vs. clinical meaning
One cell study.
Safety implication
Autophagy changes are a lab marker, not a patient outcome.
| Study | Result | People | Product |
|---|---|---|---|
| 25 | Raised LC3 II/I ratio; lowered mTOR phosphorylation at S2481 and 4E-BP1 and p70 S6K signals. | Human NSCLC cells | (-)-Guaiol, reversed by MHY1485 |
M2 macrophage marker (CD206)
Lowered in trials
A protein on the surface of M2-type macrophages, the immune cells that tend to help tumours grow.
Very low certaintyResults and what it means
Why it was measured
Used to see whether a compound shifts immune cells away from the tumour-helping type.
Statistical vs. clinical meaning
Two mouse papers from the same network; no numbers in the abstracts.
Safety implication
A lab marker, not a patient outcome.
Leishmania parasite killing (IC50)
Lowered in trials
The concentration that kills half the parasites in a dish.
Very low certaintyResults and what it means
Why it was measured
Shows how potent a compound is against the parasite before animal tests.
Statistical vs. clinical meaning
Dish tests only.
Safety implication
A lab potency number, not a patient outcome.
| Study | Result | People | Product |
|---|---|---|---|
| 9 | Guaiol IC50 0.01 ug/mL against intracellular amastigotes; oil 0.16 ug/mL; macrophages safe up to 100 ug/mL. | L. amazonensis in macrophages | Guaiol / Aloysia gratissima oil |
| 1 | Bulnesia sarmientoi oil (guaiol 48.29%) among the more active oils, IC50 54.05 to 162.25 ug/mL across the 8 most active. | L. amazonensis promastigotes | 16 essential oils |
Insect or larval death (LD50 / LC50)
Raised in trials
The dose or concentration that kills half the insects or larvae in a test.
Very low certaintyResults and what it means
Why it was measured
Shows how potent a compound is as an insecticide.
Statistical vs. clinical meaning
Insect tests.
Safety implication
Says nothing about people.
| Study | Result | People | Product |
|---|---|---|---|
| 13 | Contact LD50 0.07 and 8.9 mg/larva; fumigation LC50 3.5 and 16.9 uL/L. | Moth larvae and houseflies | Guaiol |
| 8 | Callitris extract LC50 0.23 to 38.95 mg/L (Culex) and 0.69 to 306.43 mg/L (Aedes); guaiol part less active than the distillate. | Mosquito larvae | Callitris glaucophylla extracts and guaiol |
Fungal growth stopped (MIC)
Lowered in trials
The lowest concentration that stops visible growth of a fungus or yeast in a dish.
Not enough evidenceResults and what it means
Why it was measured
A standard lab measure of antifungal potency.
Statistical vs. clinical meaning
Whole oils; dishes only.
Safety implication
A lab number, not a patient outcome.
| Study | Result | People | Product |
|---|---|---|---|
| 22 | MIC 3.9 and 0.975 ug/mL against Candida krusei for the two whole oils. | Fungal isolates | Callitris heartwood oils (guaiol 30.2% and 16.1%) |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 5
- Almost nothing is known about safety in people. No trial, case report or safety study of guaiol in people was found. Guaiol is a natural part of some plants and of cannabis flower, but no one has measured side effects, the right amount or the risks of taking it on its own. None
- Chemical-database notifications list no hazard class. PubChem summarises 234 company reports on the pure chemical, and none of them notified a hazard class. That is a paperwork finding about the pure chemical, not proof of safety, and it does not cover heating, inhaling or use inside cannabis. Authoritative guidance 19
- In dishes it kills cells, including some normal ones. The lung cancer work shows guaiol damages DNA repair and growth signals to kill tumour cells in dishes. A whole Bulnesia extract that contains guaiol was less toxic to normal lung cells than to cancer cells, but it still killed normal cells at higher concentrations. In macrophages, pure guaiol was reported safe up to 100 micrograms per mL in one test. None of this tells us what happens in a person. Laboratory research 24 23 9
- If guaiol comes with THC, the THC risks apply. Guaiol is a minor part of cannabis flower. Cannabis that contains THC carries risks of impairment, anxiety, dependence and, in people at risk, psychosis. Guaiol has not been shown to make these better or worse. Observational 7 12 16
- Do not use guaiol or wood oils in place of cancer care. Guaiol has only been studied in cells and animal models. It is not a cancer treatment. If you have lung cancer or symptoms that worry you, a doctor should be involved. Expert opinion 24 29
Side effects 4
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Side effects of guaiol alone in people No human data. The absence of reports is not evidence of safety. | Not established | Unknown Unknown | None |
| Skin or eye irritation, allergy to wood oils PubChem lists no hazard notified for the pure chemical. No patch test or allergy study of guaiol was found. Essential oils that contain it are mixtures and may behave differently. | Not established | Unknown Unknown | None 19 |
| Damage to normal cells at high concentration (dishes) A whole Bulnesia extract killed normal MRC-5 lung cells at 61.1 micrograms per mL, compared with 18.1 to 24.7 for lung cancer lines. | Not established | Not applicable (lab) Not applicable | Laboratory research 23 |
| Cannabis-related effects when guaiol comes in cannabis (impairment, anxiety, dependence, vomiting syndrome) Caused by cannabis with THC, not shown to come from guaiol. | 22% of people who use cannabis meet criteria for a cannabis use disorder (meta-analysis); these are cannabis figures, not guaiol figures | Variable Usually improves when cannabis is stopped (vomiting syndrome: 96.8% in a review) | Systematic review 12 17 16 |
Liver
No human case of liver injury from guaiol was found, and no animal liver-toxicity study of pure guaiol was found. LiverTox was not read for this page. The rat blood-level study used a plant extract and did not report liver tests in its abstract. 26
How often. No rate can be given.
Monitoring. No agency monitoring advice for guaiol was found.
This is a safety connection. It is not evidence that Guaiol supports liver health.
Medicines and supplements 4
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| THC and other cannabis compounds cannabis | Guaiol sits in cannabis flower alongside many other compounds. No study measured whether guaiol changes THC's effects. | Unknown. | None Not enough evidence 7 12 | Do not assume a terpene makes THC safer or milder. The THC risks (impairment, anxiety, dependence) still apply. |
| Alcohol, sedatives and other medicines that affect the brain general | No study of guaiol with these. The caution is general for cannabis with THC. | Unknown for guaiol. | None Not enough evidence 16 | Ask a doctor or pharmacist before combining cannabis or plant oils with other medicines. |
| Medicines broken down by liver enzymes (CYP enzymes) drug-metabolism | No study of guaiol on human CYP enzymes was found. | Unknown. | None Not enough evidence | Ask a pharmacist if you take medicines with narrow safety margins, such as blood thinners or anti-seizure medicines. For cannabis, the main interaction concerns are with CBD and THC, not guaiol. |
| Cancer treatment treatment | The lung cancer papers are laboratory work. No study tested guaiol with chemotherapy or immunotherapy in people. | Unknown. | Laboratory research Not enough evidence 24 | Tell your oncology team about any plant extract, oil or cannabis product you use. |
Who should check first 7
| Situation | Advice | Evidence |
|---|---|---|
| Pregnancy and breastfeeding | No safety data exist for guaiol. Cannabis use in pregnancy has been linked to higher autism diagnosis rates in children in one large registry study, with possible residual confounding. Avoid cannabis and concentrated plant oils unless a doctor says otherwise. | Cohort study 6 |
| Children, teenagers and young adults | No data on guaiol. In young people who use cannabis weekly or daily, the risk of developing dependence was 33% in cohort data. Cannabis with THC is not advised for teenagers. | Systematic review 12 |
| Older adults | No guaiol data. Older adults are more sensitive to sedatives and falls; ask a doctor about cannabis. | Expert opinion |
| Mental health conditions, psychosis risk, anxiety | Daily use of high-THC cannabis was linked to nearly five times higher odds of psychotic disorder in a case-control study (association, not proof of cause). People with a personal or family history of psychosis should be especially careful. | Case control 7 |
| Driving and machinery | Cannabis impairment is linked to a small to moderate rise in crash risk. Guaiol alone has not been studied. | Meta-analysis 16 |
| Regular heavy cannabis users with repeated vomiting | Cannabinoid hyperemesis syndrome is cyclic vomiting after regular cannabis use. It usually settles when cannabis is stopped. See a doctor. | Systematic review 17 |
| Anyone with lung cancer or other serious illness | Do not use guaiol, wood oils or cannabis as a substitute for treatment. | Expert opinion 24 |
Overdose, product quality and regulators
Summary. No toxicity study of guaiol alone in people or animals was found. The only animal data are mouse tumour models (tolerability not described in the abstracts) and one rat blood-level study of a plant extract.
Animal. Mouse tumour models gave no toxicity figures in the abstracts. Rats given a Ferula ferulaeoides chloroform extract by mouth (157.5 mg/kg, once) had guaiol peak at 28.63 ng/mL at 0.5 hours.
Overdose response. No data. Concentrated essential oils can be harmful if swallowed; keep them away from children and call a poison centre if swallowed.
Genotoxicity. The authors report that guaiol led to double-strand DNA breaks in lung cancer cells, which is how it killed them. No test in normal human cells or in people was read.
Terpene amounts on cannabis labels are not reliable guides. We found no study of whether label figures for guaiol are right, and the label-accuracy papers we found for cannabis products did not have results we could read.
Names and amounts vary. Our own lab data show guaiol in 59 named strains, each as one commercial sample; the same name has up to 6.7 times different values between samples (Blue Dream). Strain names are unreliable labels. 15
Label accuracy studies exist but were not read. JAMA papers tested label accuracy of cannabis edibles (2015) and CBD products sold online (2017). The PubMed records have no results text, so this page states none. 21 2
Different measures are not comparable. Dried-flower content (our lab data), steam-distilled oil percentages (South African cultivar oils: 0.17 to 2.60%) and extracts are different measures and should not be compared. 14 15
| Body | Action | Date |
|---|---|---|
| PubChem (US National Library of Medicine), summarising company notifications to the ECHA C&L Inventory (Global/EU database) | Reports that guaiol does not meet GHS hazard criteria in 100% (234 of 234) of company reports; no hazard statements notified. source | 2026-10-25 |
When to get medical help
- Someone has swallowed concentrated essential oil or a plant extract and is vomiting, drowsy, coughing, struggling to breathe or has a burning mouth (get emergency help and call a poison centre).
- A rash that spreads quickly, blisters or swelling of the face or lips after skin contact with a plant oil.
- After cannabis: severe confusion, hallucinations, thoughts of harming yourself or others, chest pain, fainting, or repeated vomiting that does not stop.
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What is guaiol?
Is guaiol the same as champacol?
Yes. PubChem lists champacol, guaiac alcohol and (-)-guaiol as names for the same molecule (CAS 489-86-1).
Where is guaiol found?
Does guaiol treat cancer?
Has guaiol been tested in people?
We found no human trial and no case report of guaiol on its own.
Is guaiol safe?
Does guaiol change how cannabis feels?
How much guaiol is in cannabis?
It varies a lot. In our lab data, 59 named strains each from one commercial sample ranged about 28-fold, and the same strain name varied up to about 6.7-fold. See the lab numbers on the Overview tab.
Does guaiol kill bacteria, fungi or insects?
Is guaiol safe in pregnancy or breastfeeding?
There is no data on guaiol. Cannabis use in pregnancy has been linked to more autism diagnoses in one large registry study, with possible confounding. Ask a doctor.
Is guaiol the same as bisabolol?
Is guaiol legal?
We found no regulator rule for guaiol itself. Rules on cannabis concern cannabis and THC. This page gives no legal advice.
Explore by health goal
Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-25
- Last substantive update
- 2026-10-25
- How we research
- We searched PubMed and read the abstracts of about 28 sources, read PubChem for chemical identity and hazard notifications, and used our own cultivar lab-data file for the cannabis numbers. We say which sources we could not read.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown, and none will be added for guaiol. This page is information, not a recommendation to use it.
Sources 30
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Andrade MA, Azevedo CD, Motta FN et al. Essential oils: in vitro activity against Leishmania amazonensis, cytotoxicity and chemical composition.. BMC Complement Altern Med. 2016. PMID 27825341. DOI 10.1186/s12906-016-1401-9. (abstract)
- Bonn-Miller MO, Loflin MJE, Thomas BF et al. Labeling Accuracy of Cannabidiol Extracts Sold Online.. JAMA. 2017. PMID 29114823. DOI 10.1001/jama.2017.11909. (title only (no abstract results))
- Cao Y, Wu Y, Tu H et al. (-)-Guaiol inhibit epithelial-mesenchymal transition in lung cancer via suppressing M2 macrophages mediated STAT3 signaling pathway.. Heliyon. 2023. PMID 37809930. DOI 10.1016/j.heliyon.2023.e19817. (abstract)
- Carvalho VM, de Almeida FG, de Macêdo Vieira AC et al. Chemical profiling of Cannabis varieties cultivated for medical purposes in southeastern Brazil.. Forensic Sci Int. 2022. PMID 35462181. DOI 10.1016/j.forsciint.2022.111309. (abstract)
- Choudhary MI, Batool I, Atif M et al. Microbial transformation of (-)-guaiol and antibacterial activity of its transformed products.. J Nat Prod. 2007. PMID 17385913. DOI 10.1021/np068052a. (abstract)
- Corsi DJ, Donelle J, Sucha E et al. Maternal cannabis use in pregnancy and child neurodevelopmental outcomes.. Nat Med. 2020. PMID 32778828. DOI 10.1038/s41591-020-1002-5. (abstract)
- Di Forti M, Quattrone D, Freeman TP et al. The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study.. Lancet Psychiatry. 2019. PMID 30902669. DOI 10.1016/S2215-0366(19)30048-3. (abstract)
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