Rosemary is a sage. In 2017, a team studying the DNA of the sage family argued that the small genus Rosmarinus sits inside Salvia. The plant is now filed as Salvia rosmarinus.
Most of the studies below still call it Rosmarinus officinalis, the name Linnaeus gave it in 1753. The old Latin name, ros marinus, means “sea dew”.
Rosemary is eaten by the sprig, not the cup. A teaspoon of fresh leaves (0.7 g) has about 1 calorie, 0.02 g of protein and 0.1 g of fiber. It gives less than 1% of the Daily Value (the daily amount used on US food labels) of any vitamin or mineral. What it adds is flavor and plant compounds, such as carnosic acid, carnosol and rosmarinic acid.
It also holds a measurable amount of naringenin, a flavanone (a type of flavonoid): about 0.17 mg per teaspoon. Our database has measured naringenin in only 10 foods.
Most of the research tests something other than the kitchen herb: a capsule, an extract, or just the smell of the oil. In the EU, rosemary extract is also an approved food additive, E 392. It is used as an antioxidant to slow rancidity. Each study below says what was actually tested.
Health benefits of rosemary
The top findings from 24 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 →- ★Low dose helped memory speed, high dose hurtIn 28 older adults, 750 mg of dried rosemary leaf powder improved memory speed compared with placebo, and 6,000 mg made it worse. The authors call 750 mg the dose nearest normal cooking.
- ★Lower anxiety and depression scoresIn 68 students, 500 mg of rosemary twice a day for a month improved anxiety, depression and memory-problem scores more than placebo. Capsules also lowered depression and anxiety scores in people with major depression.
- ★No clear effect on liver or cholesterolIn 110 people with fatty liver, 4 g a day of rosemary powder did no better than placebo on liver enzymes, cholesterol or blood sugar. This ran for 8 weeks.
- ★No consistent change in attention or energyA single 1.7 g dose of rosemary in capsules gave only small, brief changes in 40 tired young adults. It did not consistently change attention, motivation or energy.
- ★Less anxiety before surgery from rosemary smellIn 236 patients in four groups, smelling 25% rosemary oil for 30 minutes lowered anxiety scores, as music did. This was the smell of an oil, not eating rosemary.
All 24 studies, strongest evidence first
About 22% of rosemary tea’s phenols showed up in urine
Healthy adults drank rosemary tea, and forty-eight compounds turned up in their blood and urine. Few were still in their original form: the body had changed most of them, and gut bacteria handled much of the rosmarinic acid. In total, 235 µmol (micromoles) came out in urine, or 22.3% of the amount drunk. This shows absorption, not a health effect.
Older adults: low-dose rosemary improved memory speed; the top dose worsened it
In all, 28 adults, average age 75, each took a placebo (dummy pill) and four doses of dried rosemary leaf powder, on separate days. Memory speed beat placebo at the lowest dose, 750 mg, and was worse at the highest, 6,000 mg. Other thinking measures also worsened, less consistently. The authors call 750 mg the dose nearest normal cooking and ask for longer studies of low doses.
Rosemary did not beat placebo on liver enzymes, cholesterol or blood sugar
In all, 110 people with nonalcoholic fatty liver disease took 4 g of rosemary leaf powder a day or a placebo for 8 weeks. All were also on a weight loss diet and activity plan, and neither they nor the researchers knew who got what. Both groups improved from baseline, and the rosemary group did no better than diet and activity alone, except on one marker of insulin-making cell function. The dose is far more than a meal holds.
Rosemary capsules did not consistently lift attention or energy in tired adults
In this placebo-controlled trial, 40 young adults with low energy took a single dose of 1.7 g of rosemary in capsules. Volunteers wore a nose clip to block smell, and the trial also tested 2.0 g of black pepper. Rosemary gave small, brief drops in errors (effect size 0.21) and mental fatigue (0.40) at isolated times. It gave no consistent change in attention, motivation or energy.
Rosemary for a month lowered anxiety, depression and memory-problem scores in students
In a double-blind trial, 68 university students took 500 mg of rosemary twice a day for a month, or a placebo. All scales improved more than with placebo, sleep scores included, except the time it took to fall asleep and sleep duration. All outcomes were self-rated questionnaires. The abstract does not say whether the rosemary was leaf powder or an extract.
Rosemary capsules lowered depression and anxiety scores in major depression
People with major depression took rosemary capsules twice a day for 8 weeks as an add-on treatment, or a placebo. The dried plant held 21.13 mg of rosmarinic acid per gram. Scores fell more than with placebo on the Beck Depression Inventory and on the anxiety part of a hospital scale. The authors saw better memory as a side benefit, and the abstract does not give the number of patients.
Rosemary water gave small benefits on thinking tasks in healthy adults
In this trial, 80 adults drank 250 mL of a commercial rosemary water or plain mineral water, then did computer tasks. The rosemary water was made with extract and a hydrolat (a distilled herb water). Blood flow measures also differed: deoxygenated hemoglobin (blood that has given up its oxygen) was higher in the rosemary group during the tasks. This is a drink with extract, not a kitchen herb.
A rosemary drink changed brain-wave markers of attention in a small pilot
In this pilot study, 48 adults drank a rosemary drink or a water control. Then they did a visual attention task while EEG (a brain-wave recording) tracked the brain’s response. The effect was medium in size for the P3a marker and less reliable for P3b. The authors say the links to behavior should be treated with caution.
Rosemary extract lowered anxiety scores but not salivary cortisol in healthy adults
In a crossover trial (everyone took both rosemary and the comparison), 40 people took rosemary extract for 4 weeks. Trait anxiety and a heart-rate-variability measure improved, and a single dose before a mental task lowered state anxiety. A separate 4-week safety trial in 22 adults found no clinically relevant adverse events. The authors are employees of NIPPN Corporation, which funded the work.
Rosemary extract lowered a blood marker; artery widening showed no clear change
In this before-and-after study with no placebo group, 19 healthy young volunteers took 77.7 mg of extract a day for 21 days. That daily dose held 0.97 mg of carnosol, 8.60 mg of carnosic acid and 10.30 mg of rosmarinic acid. The blood marker PAI-1 fell from 4.25 to 3.0 U/mL. Artery widening did not clearly change on average, but the share of people with poor artery function fell from 66.6% to 16.6%.
Rosemary extract capsules raised thinking-test scores in people with COPD
In a triple-blind trial, 77 people with chronic obstructive pulmonary disease (COPD), a long-term lung disease, took part. They took 500 mg capsules of a water-and-alcohol extract twice a day for two months, or corn powder. Scores on the thinking test rose. Scores for instrumental daily-life tasks rose only after adjusting for sleep apnea, and a daily-life scale for breathlessness did not change.
Breathing rosemary oil improved memory quality but slowed memory speed
This trial tested aroma, not eating. A total of 144 healthy volunteers were placed at random in a cubicle with rosemary oil, lavender oil or no odor. Then they did a computer test battery without knowing the aim. Rosemary also left people feeling more alert than the control group, while lavender impaired working memory.
Rosemary aroma: more cineole in the blood, better task scores
This small study had no comparison group. Twenty volunteers did mental arithmetic and a visual task in a room filled with rosemary aroma, and blood was drawn at the end. Higher blood levels of 1,8-cineole, a compound in the oil, went with better speed and accuracy, which argues against a simple trade-off. But this kind of link cannot show that cineole caused the gain.
Rosemary odor worked as a memory cue for word completion
Three experiments used room odors, including rosemary and lemon. With rosemary, word completion was better when the same odor was present at learning and at testing. Rosemary produced a striking context effect and left people in a more unpleasant mood than lemon. The authors think its distinctiveness and unpleasantness explain why; this tests smell as a cue, not rosemary as a memory aid.
Breathing rosemary oil raised blood pressure, heart rate and breathing rate
Twenty healthy volunteers had their nervous system activity recorded before, during and after inhaling rosemary oil, and compared with control conditions. Alpha brain waves became weaker and beta waves stronger in the front of the brain. People said they felt more active and “fresher”.
One drop of rosemary oil cut sleepiness scores in night-shift nurses
In this randomized trial, 80 nurses were split by chance into groups of 40. The rosemary group put a drop of the oil on a mask, and their sleepiness score fell from 12.15 to 8.3. The control group smelled a drop of distilled water, and its score rose from 11.41 to 13.76. Both measures were self-rated questionnaires, filled out after the smell.
Smelling rosemary oil lowered anxiety before surgery, as music did
In this randomized trial, 236 patients were split into four groups of 59: rosemary aroma, music, both together, and an aromatic placebo. The rosemary group smelled 25% rosemary oil for 30 minutes. All three active groups lowered anxiety scores. Aroma alone had the largest effect, and the combination the smallest.
Oil aromas did not differ from no treatment for dialysis memory problems
In this randomized trial, 86 people on hemodialysis (a machine cleans their blood) were split into groups. The oil groups breathed rosemary, lavender or orange oil on gauze for 30 minutes, three times a week for a month. Memory problems fell over time within the rosemary and lavender groups, but the four groups did not clearly differ from each other. Medication adherence did not change either.
Breathing rosemary oil did not change lung function
In this randomized experiment, 106 healthy people breathed peppermint, eucalyptus or rosemary oil, or had no treatment. The rosemary oil was nebulized (turned into a fine mist) and breathed for 15 minutes. None of the oils changed spirometry results, a standard breathing test. Volunteers’ expectations did not change their measured performance, but they did shape how much change people felt.
Rosemary extracts sharply cut heterocyclic amines in beef patties
This lab study tested food, not people. Heterocyclic amines form when meat is cooked at high heat. Five extracts were mixed into patties at 0.05%, 0.2% and 0.5% before cooking at 191 or 204°C. Every extract lowered both amines, MeIQx by up to 91.7% and PhIP by up to 85.3%, and adding more extract made no clear difference.
Rosemary on cooked meat gave mixed results in Saudi dishes
This lab study made Saudi dishes with 2%, 5%, 10% and 15% rosemary extract. At 2%, PhIP fell by up to 61.6% in shawerma, and total amines were seven times lower in grilled chicken. Yet total heterocyclic amines rose in beef shawerma, and a bacterial test found more mutation-causing activity in the treated shawerma and chicken than in controls. The authors call for more research.
Boiling rosemary tea longer gave more polyphenols and antioxidant activity
This lab analysis boiled rosemary and basil for 5, 10 and 15 minutes, as for an herbal tea. Rosemary boiled for 15 minutes had more polyphenols (plant compounds) and antioxidant activity than rosemary boiled for 5. In a dish test, the rosemary extract also held back Gram-positive bacteria such as Listeria monocytogenes (5 mg/mL), but not Gram-negative ones. No people were tested.
Rosemary extract improved maze learning and memory in fast-aging mice
This was a study in mice bred to age fast, not people. Mice given rosemary extract by mouth did better on a water-maze test. They had less amyloid-beta 42 (a protein linked to Alzheimer’s disease), fewer inflammation markers and more BDNF, a protein that helps brain cells grow. Gene tests found changes in genes for myelin-making cells (which insulate nerves) in the hippocampus, a memory area of the brain.
Rosemary extract slowed lung cancer cell growth in a dish
This lab study used A549 human lung cancer cells, not people. As the dose rose, cell growth and colony survival fell, and the extract pushed the cells toward cell death. Activity in the Akt, mTOR and p70S6K growth pathway also fell. The authors say animal studies are needed next.
Who should be careful with rosemary
Most people can eat rosemary freely. Take a little care if one of these applies:
- Pregnancy or breastfeeding, in medicinal amounts. The European Medicines Agency says the safety of rosemary leaf in pregnancy and breastfeeding has not been established. So it does not recommend rosemary leaf teas or extracts then. Its monograph (official summary) covers herbal medicine, 2 to 6 g of leaf a day as tea, not a sprig in a roast. Ask your doctor or midwife before going beyond cooking amounts.
- Gallstones, bile duct problems or liver disease. The agency says oral rosemary leaf preparations need medical supervision in these conditions. It does not recommend them for children under 12, for lack of data. These warnings are about teas and extracts, not cooking.
- Allergy and rosemary oil. Contact dermatitis (a skin rash from touching something) has been reported, and the agency’s review names carnosol as a major rosemary allergen. The essential oil is for use on skin only. It contains camphor, which can cause seizures in large amounts. Still, the agency found no human data linking eating rosemary extracts to seizures.
How to choose, store and eat rosemary
- Fresh: run your fingers down the stem to strip the leaves, then chop. The woody stems are tough, so remove whole sprigs before serving. A teaspoon (0.7 g) has about 1 calorie.
- Dried: dried herb is stronger, about 1 teaspoon dried for each tablespoon fresh. In 28 older adults, 750 mg of dried leaf improved speed of memory and 6,000 mg made it worse. So a little goes a long way.
- Tea: the agency lists 1 to 2 g in 150 to 250 mL of boiling water as a traditional single dose. In a lab test, tea boiled for 15 minutes held more polyphenols than tea boiled for 5.
Choose sprigs that are not discolored or damaged. Keep them in the fridge for up to a week, wrapped in a damp paper towel in an open bag. Or stand them in a glass of water under a loose bag. You can also freeze whole sprigs or chopped leaves.
Rosemary extract cut heterocyclic amines by up to 91.7% in lab-cooked beef patties. But extracts gave mixed results on real dishes in a Saudi test.
On a food label, “extract of rosemary” or E 392 is an antioxidant additive. EFSA, the EU’s food safety agency, put the highest intake from it, in children, at 0.20 mg per kg of body weight a day. That is below the temporary limit of 0.3.
Sources
- European Union herbal monograph on Rosmarinus officinalis L., folium. European Medicines Agency, HMPC. Opinion of 2024.
- Assessment report on Rosmarinus officinalis L., aetheroleum and Rosmarinus officinalis L., folium. European Medicines Agency, HMPC.
- EFSA Panel on Food Additives and Nutrient Sources added to Food. Refined exposure assessment of extracts of rosemary (E 392) from its use as food additive. EFSA Journal. 2018.
- Smith J. Rosemary adds a strong, assertive flavor to your plate. University of Illinois Extension. 2022.
- Smith M. Enhance the flavor of food with herbs. Penn State Extension. 2024.
- Pengelly A, Snow J, Mills SY, et al. Short-term study on the effects of rosemary on cognitive function in an elderly population. J Med Food. 2012.
- Salamatullah AM, Hayat K, Arzoo S, et al. Boiling technique-based food processing effects on the bioactive and antimicrobial properties of basil and rosemary. Molecules. 2021.
- Puangsombat K, Smith JS. Inhibition of heterocyclic amine formation in beef patties by ethanolic extracts of rosemary. J Food Sci. 2010.
- Awney HA, Sindi H. The effect of rosemary on the mutagenic activity of heterocyclic amines extracted from common food consumed in Saudi Arabia. Int J Food Sci Nutr. 2010.
History of rosemary
Rosemary grows wild around the Mediterranean and is native to Portugal and northwestern Spain too. A gardening book of 1823 noted that rosemary thrives best by the sea, which fits the name ros marinus. The Roman farm writer Columella is the earliest classical author to use the Latin word.
Ancient Egyptians, Romans and Greeks held rosemary sacred, according to Wikipedia. It turns up in the writing of Pliny the Elder. It is also in De materia medica by the Greek physician Dioscorides, one of the most influential herbal books in history.
Rosemary traveled with people. It was naturalized (growing wild) in China as early as 220 CE, in the late Han dynasty. A document credited to Charlemagne ordered it grown in monastic gardens and farms.
In 1338, cuttings were sent to Queen Philippa of England by her mother, Joan of Hainault, for the garden of the old palace of Westminster. It reached the Americas with European settlers in the early 17th century.
Hungary water, dated by some accounts to the 14th century, was one of the first alcohol-based perfumes in Europe. It was made mainly from distilled rosemary. The oldest surviving recipes call for distilling fresh rosemary and thyme with brandy.
Legend says it was made for a Queen of Hungary’s headaches. But those tales mostly date from the 17th century, so the details may be muddled.
Rosemary has long stood for remembrance. In Hamlet, Ophelia says rosemary is “for remembrance”. Mourners in Europe and Australia have tossed it into graves. Australians wear sprigs on ANZAC Day because the herb grows wild on the Gallipoli Peninsula, where many Australians died in World War I.
Sources
- Rosemary. Wikipedia.
- Hungary water. Wikipedia.
- Drew BT, González-Gallegos JG, Xiang CL, et al. Salvia united: the greatest good for the greatest number. Taxon. 2017.
Frequently asked questions about rosemary
Is rosemary good for you?
Rosemary is a safe, flavorful herb in cooking amounts, but a sprig has not been shown to improve health. A teaspoon of fresh leaves (0.7 g) has about 1 calorie. It gives less than 1% of the Daily Value of any vitamin or mineral.
The human trials used 750 mg to 6 g of dried leaf, extracts or just the smell of the oil. Most were small and short, so none of the evidence here is strong or moderate.
Does rosemary improve memory?
Possibly a little, but the evidence is small and mixed. In 144 volunteers, the aroma of rosemary oil raised memory quality scores but slowed memory speed. In 28 older adults, 750 mg of dried leaf improved speed of memory, while 6,000 mg made it worse.
In 86 dialysis patients, the aroma did not differ from no treatment for memory problems. And the 68-student trial that found gains used self-rated questionnaires.
Is rosemary tea good for you?
No study here tested whether rosemary tea improves health. One study in healthy adults found its polyphenols are absorbed and heavily changed by the gut. In all, 22.3% of the amount drunk showed up in urine.
A lab test found tea boiled for 15 minutes held more polyphenols than tea boiled for 5. The European Medicines Agency lists 1 to 2 g of leaf in 150 to 250 mL of boiling water as a traditional single dose.
Does rosemary oil help hair grow?
Maybe. In one trial, rosemary oil on the scalp did about as well as 2% minoxidil, a hair-loss drug. But this was oil on the skin, not food.
In 100 people with pattern hair loss, hair counts rose at 6 months but not at 3 months. There was no clear difference between rosemary oil (50 people) and minoxidil (50 people). The abstract lists no placebo group, and scalp itching was more frequent with minoxidil.
Is rosemary safe during pregnancy?
Cooking amounts are not the concern, but larger medicinal amounts have not been studied. The European Medicines Agency says safety of rosemary leaf in pregnancy and breastfeeding has not been established. It does not recommend rosemary leaf teas or extracts then. Ask your doctor or midwife before using rosemary tea, capsules or oil.
How much rosemary can you eat?
No limit exists for cooking amounts, and a teaspoon of fresh leaves weighs only 0.7 g. Trials gave 750 mg to 6 g of dried leaf, including 4 g a day for 8 weeks in a fatty liver trial. In older adults, 6,000 mg at once made memory speed worse. People with gallstones, bile duct or liver disease should ask a doctor before using teas or extracts.
Does rosemary make grilled meat healthier?
It may lower some cancer-linked compounds, but only lab and food-science tests show it. Extracts added to beef patties cut the heterocyclic amines MeIQx by up to 91.7% and PhIP by up to 85.3%.
In Saudi dishes the results were mixed. PhIP fell by up to 61.6% in shawerma, but total amines rose, and a bacterial test found more mutation-causing activity. No study followed people who eat rosemary-marinated meat.
What is E 392 on a food label?
E 392 is extract of rosemary leaf, approved in the EU as an antioxidant food additive. Permitted levels are 15 to 400 mg/kg of food, depending on the food. Its active compounds are carnosic acid and carnosol.
EFSA estimated the highest intake in children at 0.20 mg per kg of body weight a day, likely an overestimate. The temporary limit, set by JECFA (the UN and WHO expert committee on food additives), is 0.3.