Common thyme has no single chemical identity. Within the one species, Thymus vulgaris, researchers describe six chemotypes: plants that look alike but make a different dominant oil, either thymol, carvacrol, geraniol, α-terpineol, linalool or thuyanol. Thymol is the main compound of thyme, and published analyses put it at 10 to 64% of the essential oil.
A teaspoon of fresh thyme (0.8 g) has about 1 calorie and 1% of the daily value of vitamin C, so the herb flavors food more than it feeds you. The nutrition facts on this page are for fresh thyme.
Almost all the human research is on cough syrups, drops and tablets made from thyme extract, usually mixed with ivy leaf or primrose root, and on thyme oil, not on the kitchen herb. A 2023 review of trials that used kitchen amounts of herbs and spices for metabolic syndrome found 142 studies on 14 of them, and none on thyme.
Health benefits of thyme
The top findings from 20 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Less coughing in bronchitis, with thyme blendsThyme blends with ivy or primrose root cut coughing fits in acute bronchitis, by 68.7% against 47.6% on placebo in one trial. That was a thyme-ivy syrup; thyme was never tested alone.
- ★Lower anxiety and depression scores in studentsStudents rated themselves after taking 500 mg of thyme leaves twice a day for a month. Scores for memory problems, anxiety and depression fell more than with placebo, as did most sleep scores (not falling asleep or sleep length).
- ★Less period pain with thyme oil dropsIn 84 students, pain scores fell from 6.57 to 1.21 on thyme essential oil drops, against 6.18 to 3.54 on placebo. Thyme oil and ibuprofen did not differ from each other.
- ★Less activity-related cough in children with asthmaChildren aged 5 to 12 took a thyme powder syrup for a week during an asthma flare. Cough with activity fell more than on placebo, but wheezing and breathlessness did not differ.
- Population studyThyme tea linked to less period painEthiopian schoolgirls who drank thyme tea had 63.2% lower odds of period pain. This was a survey based on what girls reported drinking, so it does not prove cause.
All 20 studies, strongest evidence first
Cough remedies made from thyme with ivy or primrose root beat placebo in a pooled analysis of 4 trials (relative risk 1.40)
Meta-analysis of 34 randomized trials (7,083 people) of herbal medicines for cough with colds and upper respiratory infections, searched through March 2012. Four trials tested ivy, primrose and thyme preparations, never thyme alone, so the result cannot be credited to thyme itself. The authors rated the evidence strong; most studies had a low risk of bias.
A thyme and ivy leaf syrup for 11 days cut coughing fits by 68.7%, against 47.6% on placebo, in adults with acute bronchitis
Double-blind trial of 361 outpatients with acute bronchitis and a productive cough, taking 5.4 ml of a thyme-ivy fluid extract syrup three times a day. A 50% drop in coughing fits came 2 days earlier than on placebo, and at the end more people had responded on the severity score (96.2% vs 74.7%). Side effects did not differ from placebo.
A thyme and primrose root tablet for 11 days cut coughing fits by 67.1%, against 51.3% on placebo, in adults with acute bronchitis
Double-blind trial of 361 outpatients with acute bronchitis and a productive cough, taking 1 tablet of dry thyme and primrose root extracts three times a day. A 50% drop in coughing fits came about 2 days earlier than on placebo, and at the end more people had responded on the severity score (92.9% vs 75.8%). Side effects did not differ from placebo.
A thyme and primrose root extract for 7 to 9 days left 58.7% of people symptom free, against 5.3% on placebo, in acute bronchitis
Double-blind trial of 150 outpatients with untreated acute bronchitis for less than 48 hours, taking 1 ml of thyme fluid extract with primrose root tincture 5 times a day. The severity score fell from 12.0 to 1.0 on the extract and from 11.7 to 6.5 on placebo. No serious side effects occurred.
Thyme leaves, 500 mg twice a day for a month, lowered scores for memory problems, anxiety, depression and poor sleep in university students
Randomized trial in 106 students given 500 mg of Thymus vulgaris leaves twice a day or a placebo. That is about 1 g a day, roughly a teaspoon of fresh leaves. Scores on all the scales fell more with thyme, except the sleep latency and sleep duration parts of the sleep score. The abstract gives no effect sizes, and self-rated questionnaires are open to placebo effects.
Thyme powder as a syrup for a week reduced activity-related cough in children having an asthma flare
Triple-blind trial in 60 children aged 5 to 12 who took thyme powder syrup (20 mg per kg every 8 hours) or a placebo syrup on top of usual treatment. Cough with activity fell more on thyme (p = 0.042) and FEV1 differed (p = 0.048), but wheezing, breathlessness and the other lung measures did not.
Inhaling thyme oil 3 times a day for 5 days eased symptoms such as cough and shortness of breath in hospital patients with COVID-19
Randomized trial in 140 COVID-19 patients, 70 of whom inhaled thyme oil while 70 got routine care only, so there was no placebo. Oxygen saturation rose and pulse, breathing rate and body temperature fell; blood pressure did not change. The oil was inhaled, not eaten.
Thyme essential oil drops for period pain cut pain scores from 6.57 to 1.21, against 6.18 to 3.54 on placebo
Triple-blind trial in 84 students with period pain, randomized to thyme (Thymus vulgaris) essential oil, ibuprofen or placebo, given every 6 hours from the start of pain for two cycles. Ibuprofen fell from 5.30 to 1.48, and thyme and ibuprofen did not differ from each other.
A 5% thyme mouthwash for 5 days improved oral health about as well as chlorhexidine in patients on ventilators
Triple-blind trial in 46 intensive care patients on ventilators, 23 per group, comparing a 5% thyme mouthwash with 0.2% chlorhexidine. Both improved oral health scores, and thyme scored higher on some parts, such as oral hygiene (p = 0.004). No side effects were reported. It is a rinse, not food.
A thyme-ivy syrup for 14 days lowered interleukin-6 by 4.9 pg/mL against 0.9 with no treatment in mild COVID-19, in a tiny pilot
Open-label pilot trial in 21 outpatients: 13 took 5.4 ml of thyme-ivy syrup three times a day and 8 took nothing. The syrup group had a higher viral load and more comorbidities at the start, so the authors call the differences exploratory and ask for a larger trial.
In a three-way trial, a single ivy extract worked as well as two thyme combinations for acute bronchitis, and better than thyme-ivy
Open-label randomized trial of 325 adults comparing an ivy extract with a thyme-ivy and a thyme-primrose product, scored on the severity score at day 7. Ivy was better than thyme-ivy (p < 0.0001) but not clearly better than thyme-primrose (p = 0.0607), so adding thyme was not shown to add benefit. Three of the five authors work for a drug company, Engelhard Arzneimittel.
After a thyme extract tablet, thymol reached the blood only as thymol sulfate, peaking after 2 hours
Study in 12 healthy volunteers who took one tablet equal to 1.08 mg of thymol. No thymol itself was found in blood or urine. Thymol sulfate peaked at 93.1 ng/ml, and 16.2% of the dose came out in 24-hour urine as thymol sulfate and thymol glucuronide.
Schoolgirls who drank thyme tea had 63.2% lower odds of period pain in an Ethiopian survey
Case-control study of 252 schoolgirls in Ethiopia, 86 with period pain and 166 without. Thyme tea drinking was reported by 22.1% of the girls with pain and 33.7% of those without. Diet came from an interview, so the link may not be cause.
A thyme-based herbal cough medicine worked at least as well as synthetic drugs in a matched comparison of 7,783 patients with acute bronchitis
Matched-pair comparison of the herbal product Bronchipret with three groups of other treatments. Adults on the herbal product had markedly fewer adverse reactions. It was neither randomized nor blinded, so the authors ask for confirmation in randomized trials.
In a pharmacy survey, cough severity scores fell from 8.7 to 2.4 in people taking a thyme-ivy extract
Uncontrolled study of 730 analyzed patients in 305 German pharmacies who bought thyme-ivy drops (BNO 1200) for an acute cough. Treatment lasted 7.0 days on average, 87.2% reported a clinically relevant drop in cough severity, and 98.0% rated tolerability good or very good. With no placebo group, some of this is natural recovery. Three of the five authors work for the drug company Bionorica.
In cell tests, thyme extract blocked influenza A virus in a dose-dependent way but not rhinovirus
Lab study in cultured cells comparing thyme and pelargonium extracts with the drugs ambroxol, bromhexine and N-acetyl cysteine. Thyme showed little toxicity to the cells. Cells in a dish say little about what happens in a person who drinks thyme tea.
Thyme extract increased cilia beating in lab-grown airway tissue from people with COPD
A commercial thyme extract was tested on a 3D model of human COPD airway lining. It raised cAMP from 12 hours after treatment and lowered extracellular calcium. Cilia sweep mucus out of the airways. This is a tissue model, with no patients.
In rats with lung inflammation, a thyme-ivy syrup reduced white blood cells in lung tissue and mucus-producing goblet cells
Rats given lung inflammation received the syrup at 1 to 10 times the human daily dose. In human white blood cells, a syrup analogue also blocked release of leukotrienes (inflammation signals). Four of the seven authors work for Bionorica, the drug company that makes the syrup.
Thymol, the main compound of thyme, reduced allergic airway inflammation in mice with asthma-like disease at 4, 8 and 16 mg per kg
Mice with asthma-like inflammation (triggered by the egg protein ovalbumin) were given thymol by mouth before each challenge. It lowered IgE, inflammatory cells and the signals IL-4, IL-5 and IL-13 in lung fluid, and it reduced airway hyperresponsiveness, apparently by blocking NF-κB. This is isolated thymol in mice.
In cell tests, ivy raised an airway-relaxing signal, but the thyme part did not and may in part work against it
Cell-line experiments compared an ivy preparation, an ivy and thyme combination and a thyme preparation on the β2-adrenergic receptor, which the authors link to thinning mucus and relaxing airway muscle. A rise in cAMP was seen only with ivy. The authors conclude the thyme fraction may in part have a negative effect on this signal.
Who should be careful with thyme
Most people can eat thyme freely. Take a little care if one of these applies:
- Allergy to the mint family. The European Medicines Agency (EMA) lists allergy to thyme or other plants of the mint family (Lamiaceae) as a reason not to use thyme medicines.
- Pregnancy and breastfeeding. The EMA says the safety of thyme herb medicines, including tea, has not been established in pregnancy and breastfeeding and advises against them. Its monograph does not address the small amounts used in cooking.
- Children and long-lasting cough. The EMA does not recommend most thyme medicines for children under 12, and says to see a doctor if a cough lasts more than a week or comes with fever, breathlessness or pus-colored phlegm.
How to choose, store and eat thyme
- Fresh or dried: dried herbs are usually three to four times stronger than fresh, so use about a third to a quarter as much.
- Strip the leaves: rinse the sprigs gently, pat them dry and slide your fingers down the stem to pull off the leaves.
- Tea: the EMA describes 1 to 2 g of cut thyme herb in 150 ml of boiling water, 3 to 4 times a day, as a traditional remedy for chesty cough with a cold. It rests on long use, not on trials of tea.
Look for vibrant green leaves and skip sprigs that are yellow or have dark spots. Wrapped in a moist paper towel inside a plastic bag in the fridge, fresh thyme keeps for several days, and thyme freezes or dries well for longer. Dried herbs keep their best quality for up to a year in an airtight container in a cool, dark place. The cough trials above used licensed syrups, drops and tablets, and the oil trial had people inhale it, so none of them shows what a sprig in soup does.
Sources
- Community herbal monograph on Thymus vulgaris L. and Thymus zygis L., herba. EMA/HMPC/342332/2013. European Medicines Agency. 2013.
- Thymi herba. European Medicines Agency, herbal medicine summary.
- Thyme. Purdue Extension FoodLink.
- Food preservation: preserving herbs, freezing and drying. Ohio State University Extension.
History of thyme
Thyme is the leafy top of plants in the genus Thymus, about 350 aromatic perennial herbs and small shrubs of the mint family. Thymes are native to North Africa, the Levant and southern Europe, and wild thyme in the Levant is where it might first have been cultivated. Cooks mostly use common thyme, Thymus vulgaris, which is a standard part of a bouquet garni and of herbes de Provence.
Old stories say the ancient Greeks burned thyme as incense in temples and believed it gave courage, and that the Romans carried it across Europe to purify rooms. In the Middle Ages women are said to have given knights thyme leaves for courage, and sprigs went under pillows to keep nightmares away. The sources for these tales are thin, so treat them as folklore.
The chemistry has firmer dates. German chemist Caspar Neumann first isolated thymol from thyme oil in 1719 and called it Camphora Thymi. French chemist Alexandre Lallemand named it and worked out its formula in 1853, and Swedish chemist Oskar Widman first made it in the lab in 1882. In the 1910s thymol was used in the United States against hookworm infection, and today it is an active ingredient in some mouthwashes, such as Listerine.
Plant scientists only recently worked out how thyme builds its signature compound. In 2021 a team identified the enzymes that thyme, oregano and other mint-family plants use to turn γ-terpinene into thymol and carvacrol: cytochrome P450 enzymes and a short-chain dehydrogenase. Even the name has traveled. Linnaeus named the grayling fish genus Thymallus in 1758, reportedly for the faint thyme-like smell of its flesh.
Sources
- Thyme. Wikipedia.
- Thymus (plant). Wikipedia.
- Thymol. Wikipedia.
- Thompson JD, Chalchat JC, Michet A, Linhart YB, Ehlers B. Qualitative and quantitative variation in monoterpene co-occurrence and composition in the essential oil of Thymus vulgaris chemotypes. J Chem Ecol. 2003.
- Salehi B, Mishra AP, Shukla I, et al. Thymol, thyme, and other plant sources: health and potential uses. Phytother Res. 2018.
- Krause ST, Liao P, Crocoll C, et al. The biosynthesis of thymol, carvacrol, and thymohydroquinone in Lamiaceae proceeds via cytochrome P450s and a short-chain dehydrogenase. Proc Natl Acad Sci U S A. 2021.
- Mackonochie M, Rodriguez-Mateos A, Mills S, Rolfe V. A scoping review of the clinical evidence for the health benefits of culinary doses of herbs and spices for the prevention and treatment of metabolic syndrome. Nutrients. 2023.
Frequently asked questions about thyme
Is thyme good for you?
In small ways, but the evidence is thin. A teaspoon of fresh thyme (0.8 g) has about 1 calorie, 0.1 g of fiber and 1% of the daily value of vitamin C, so it adds flavor more than nutrition. Most of the research is on extracts: a pooled analysis of 4 trials found thyme combined with ivy or primrose root beat placebo for cough, but no study here tested thyme as a food for a health outcome.
Does thyme help a cough?
Thyme extract mixtures seem to, but plain thyme is untested. In two trials of 361 people with acute bronchitis, coughing fits fell 68.7% on a thyme-ivy syrup and 67.1% on a thyme-primrose tablet, against 47.6% and 51.3% on placebo. Everyone improved, so part of the drop is natural recovery, and a 2025 trial found a single ivy extract worked as well as two thyme combinations. See a doctor if a cough lasts more than a week.
Is thyme tea good for a cough?
It is a traditional remedy, but no trial here tested tea for cough. The EMA lists thyme herb tea for chesty cough with a cold, based on long use, at 1 to 2 g of herb in 150 ml of boiling water, 3 to 4 times a day for teens and adults. Most thyme preparations are not recommended under 12.
How much thyme can you eat a day?
No study sets a limit for the kitchen herb, and cooking amounts are small: a teaspoon of fresh leaves weighs 0.8 g. The one trial that gave thyme leaves used 500 mg twice a day for a month in 106 students. Teas and extracts used as medicine are another matter, and the EMA says to ask a doctor if symptoms last more than a week.
Is fresh or dried thyme better?
Neither is better for health, they differ in strength. Dried herbs are usually three to four times stronger than fresh, so use about a third to a quarter as much. No study here compared the two, and the nutrition facts on this page are for fresh thyme.
Is thyme safe during pregnancy?
The small amounts used in cooking are not flagged by the sources used here, but medicinal use is not recommended. The EMA says the safety of thyme herb medicines in pregnancy and breastfeeding has not been established. Ask your midwife or doctor before using thyme syrups, strong teas or oil.
How many calories and vitamins are in thyme?
Very few: a teaspoon of fresh thyme (0.8 g) has about 1 calorie, 0.04 g of protein, 0.1 g of fiber, 1.28 mg of vitamin C (1% of the daily value) and 0.14 mg of iron. Nothing reaches 5% of your day. It does have measured flavonoids, 0.38 mg a teaspoon, mostly luteolin. Gram for gram it is richer, with 160 mg of vitamin C per 100 g, but nobody eats that much.
Does thyme help with period pain?
Small trials say it might, but the evidence is thin. In 84 students, thyme essential oil drops cut pain scores from 6.57 to 1.21, against 6.18 to 3.54 on placebo, much like ibuprofen. In a survey of 252 Ethiopian schoolgirls, thyme tea drinkers had 63.2% lower odds of period pain, a link and not proof.