Materia Medica

Rosemary

Salvia rosmarinus

AKA Rosmarinus officinalis, Dew of the Sea

Salvia rosmarinus Spenn. (syn. Rosmarinus officinalis L.). Part used: leaf and flowering tops. Family: Lamiaceae (mint family). Energetics: warming, drying, pungent and bitter.

Key Takeaways

Rosemary is a warming, aromatic member of the mint family. Since 2017 it has been classed as a sage, Salvia rosmarinus.
Traditional sources describe it as a stimulant for digestion, circulation, and the nervous system, and as a scalp and hair rinse.
Human trials are small. Low doses of leaf powder improved a memory-speed measure in older adults, while high doses impaired it. Rosemary oil on the scalp matched 2 percent minoxidil for hair count over six months in one trial that had no placebo group.
Culinary use is considered safe. Therapeutic doses are not recommended in pregnancy, the essential oil is not for internal use, and a rosemary extract reduced iron absorption from a meal in one human study.
Dosing depends on the source. Commission E gives 4 to 6 grams of leaf daily; the EMA monograph gives 1 to 2 grams per cup of tea.
Rosemary grows well in containers anywhere in the US. It needs full sun, fast drainage, and less water than most herbs.

Educational content only. This monograph is not medical advice and is not a substitute for care from a qualified practitioner. Do not stop or change a prescribed medication based on anything you read here. If you are pregnant, nursing, or taking medication, talk with your doctor or a clinical herbalist first.

Botany and the Name Change

Rosemary is an evergreen shrub with needle-like leaves that are dark green on top and pale underneath, and small blue to white flowers. King's American Dispensatory describes it as 2 to 4 feet tall, native to the countries around the Mediterranean, and grown in nearly every garden for its scent.¹ It tolerates drought, poor soil, and salt air.

The Latin name has changed. Linnaeus placed rosemary in its own genus, Rosmarinus, in 1753. A 2017 DNA study found that Rosmarinus and four other small genera sit inside the sage genus, and the authors concluded the botanical community was best served by folding them all into Salvia.⁸ The accepted name is now Salvia rosmarinus. Books, labels, and most research still say Rosmarinus officinalis, and both names refer to the same plant. Rosemary is therefore a close relative of garden sage, and the two share several compounds, including camphor and rosmarinic acid.

Energetics

Warming, drying, pungent and bitter. Rosemary moves blood toward the surface and the head, warms cold digestion, and dries damp conditions. Cook's Physiomedical Dispensatory calls the leaves diffusively stimulating and relaxing, with a warm infusion acting as a mild diaphoretic (promotes sweating) and nervine (acts on the nervous system).³ It suits people who run cold, with sluggish digestion, cold hands, low energy, and a foggy head. It is a poor match for people who run hot, with irritability, flushing, or dry, inflamed tissue.

Constituents

Rosemary carries two chemically different groups, and the split decides how you prepare it (see Preparations).

Volatile oil (about 1 to 2.5 percent of the dried leaf): 1,8-cineole, camphor, alpha-pinene, camphene, borneol, and bornyl acetate. This is the scent and the warming, carminative (gas-relieving) action. The oil leaves with steam, so infusions must be covered.
Rosmarinic acid: a water-soluble phenolic acid shared with lemon balm and sage. Studied in the laboratory for antioxidant and anti-inflammatory activity. Extracts well in hot water.
Carnosic acid and carnosol: fat-soluble diterpenes concentrated in the leaf. Most current laboratory interest in rosemary as an antioxidant and nerve-protective plant centers on these two. They extract in alcohol and oil, not water.
Flavonoids: apigenin, diosmin, luteolin, and their glycosides.
Triterpenes: ursolic acid and oleanolic acid, studied for hair and skin applications in laboratory work.
Tannins and a bitter principle: noted by King's as the source of the astringent, bitter taste.¹

Nearly all of the rosmarinic acid and carnosic acid studies are laboratory or animal work using isolated compounds or concentrated extracts. They describe mechanisms. They do not show what a cup of rosemary tea does in a person.

Traditional Use

Western Herbalism

Memory and the head. Rosemary has been associated with memory since ancient Greece. Grieve records the oil as a nervine and stomachic used for headache, and describes rosemary wine, made by steeping fresh sprigs in white wine, taken in small amounts for a weak heart with palpitation.⁴
Digestion. Grieve lists the oil's carminative properties and calls it an excellent stomachic (a digestive tonic).⁴ Commission E approved the leaf internally for dyspeptic complaints (indigestion), and the EMA monograph carries the same traditional indication for dyspepsia and mild gut spasm.⁵⁶
Hair and scalp. Grieve says spirit of rosemary was used chiefly in hair lotions to stimulate the hair bulbs and prevent premature baldness, and that a cold infusion of leaf and flower was one of the best hair washes known, effective against dandruff.⁴ The 1911 British Pharmaceutical Codex still listed a rosemary hair lotion. I cover the modern version of this use, along with nutrition and other herbs for hair, in Herbs and Supplements for Healthy Hair and Faster Growth.
Joints and circulation. Hungary Water, a distilled rosemary spirit dating to at least the 1300s, was rubbed into stiff limbs and gouty hands and feet.⁴ Commission E approved the leaf externally as supportive therapy for rheumatic complaints and circulatory problems, and the EMA monograph lists rosemary baths for minor muscle and joint pain and minor peripheral circulatory disorders.⁵⁶
Menstruation. Cook used the warm infusion for menses suppressed by exposure to cold and for painful menstruation.³ King's lists rosemary as an emmenagogue.¹ This use is the reason therapeutic doses are avoided in pregnancy.

The Eclectics

The Eclectic physicians of the 1800s used rosemary less than their European counterparts. King's American Dispensatory records it as stimulant, antispasmodic, and emmenagogue, seldom used internally in the United States except as a fragrant addition to liniments and ointments, with the oil dosed at 3 to 6 drops.¹ Spirit of rosemary was used as a nerve stimulant and applied externally for local pain.

What the Research Shows

Each card lists the preparation, the design, and the weak points, so you can weigh the claim yourself. Rosemary has far more laboratory data than human data. The four trials below are the strongest human work available.

Small randomized crossover trial

Low-dose leaf powder and memory speed in older adults

Preparation: Dried rosemary leaf powder at 750, 1,500, 3,000, and 6,000 mg, stirred into tomato juice, compared with plain juice.
Design: Randomized, placebo-controlled, double-blind crossover in 28 adults with an average age of 75. Each person received every dose on separate days, with computerized cognitive testing at 1, 2.5, 4, and 6 hours after the drink (Pengelly et al., Journal of Medicinal Food, 2012).⁹
Result: Participants scored better on speed of memory after the 750 mg dose than after placebo. After 6,000 mg they scored worse. Measures of working memory quality and attention were impaired at several doses.
Weak points: Twenty-eight people, single doses, and effects measured over one afternoon. The mixed results across measures make this a signal for low doses, not proof. Several authors are herbal-medicine researchers, and the funding source is not stated in the abstract.

Read the study

Small randomized trial

Oral rosemary and memory, mood, and sleep in students

Preparation: 500 mg rosemary in capsules, twice daily for one month, compared with placebo capsules.
Design: Double-blind randomized controlled trial in 68 university students in Iran (Nematolahi et al., Complementary Therapies in Clinical Practice, 2018).¹⁰
Result: The rosemary group reported better prospective and retrospective memory, lower anxiety and depression scores, and better sleep quality than the placebo group after one month.
Weak points: All outcomes were self-reported questionnaires, not objective tests. Sixty-eight healthy young adults over four weeks. The abstract does not specify how the plant material was processed. No industry funding is stated; the work came from a university herbal medicine research center.

Read the study

Randomized comparative trial, no placebo

Rosemary oil versus 2 percent minoxidil for pattern hair loss

Preparation: Rosemary essential oil applied to the scalp, compared with 2 percent minoxidil solution, for six months.
Design: One hundred people with androgenetic alopecia (hormone-related pattern hair loss) were randomly assigned to one treatment or the other, with microphotographic hair counts at baseline, three months, and six months (Panahi et al., Skinmed, 2015).¹¹
Result: Neither group showed a change at three months. At six months both groups had a significant increase in hair count, with no difference between them. Scalp itching was reported more often in the minoxidil group.
Weak points: There was no placebo group, so the trial cannot show that either treatment beat doing nothing. It compared against 2 percent minoxidil rather than the 5 percent strength more often used. One trial, six months, not yet replicated at this size. No industry funding is stated. I discuss this trial and how to use rosemary on the scalp in the hair growth article.

Read the study

Human absorption study

Rosemary extract and iron absorption

Preparation: A phenolic-rich rosemary extract added to a test meal, with iron absorption measured using radiolabeled iron.
Design: Controlled crossover in healthy women, comparing the same meal with and without the extract (Samman et al., American Journal of Clinical Nutrition, 2001).¹²
Result: Nonheme iron absorption (the plant form of iron) fell by 21 percent when the rosemary extract was present. Green tea extract in the same study reduced it by 28 percent.
Weak points: The study used a concentrated food-industry extract rather than leaf or tea, so the size of the effect from culinary or tea use is unknown. Funded by the Danish Ministry of Education, with no industry sponsor stated.

Read the study

Dosing Perspectives

Dosing is a perspective, not a single number. The figures below are attributed to named sources and left to disagree where they do. They describe how practitioners and regulators have used rosemary. They are not a prescription for you.

Source	Preparation	Dose	Context
German Commission E⁵	Dried leaf, or equivalent preparation	4 to 6 g daily	Dyspeptic complaints (internal); rheumatic and circulatory support (external)
EMA herbal monograph, 2024⁶	Herbal tea	1 to 2 g per cup, 2 to 3 times daily; 2 to 6 g per day	Dyspepsia and mild gut spasm; adults and adolescents 12 and older
EMA herbal monograph, 2024⁶	Bath additive	50 g decocted in 1 liter of water, or added directly; 2 to 3 baths weekly	Minor muscle and joint pain, minor peripheral circulation complaints
David Hoffmann, Medical Herbalism⁷	Infusion	1 to 2 teaspoons dried herb per cup, covered, 10 to 15 minutes, three times daily	Carminative, circulatory, and nervine use
David Hoffmann, Medical Herbalism⁷	Tincture, 1:5 in 40 percent alcohol	1 to 2 ml, three times daily	Same uses, in formula
King's American Dispensatory, 1898¹	Essential oil	3 to 6 drops (historical)	Stimulant, antispasmodic. Listed for the record; internal oil use is not recommended today
Maude Grieve, A Modern Herbal⁴	Cold infusion of leaf and flower	Used as a hair rinse	Scalp, dandruff, hair
Pengelly trial, 2012⁹	Dried leaf powder	750 mg (single dose)	The dose that improved memory speed; 6,000 mg impaired it

The regulatory sources and Hoffmann agree on a daily leaf dose of a few grams, which is one to three cups of tea. The one dose-ranging trial in humans found the low end helpful and the high end harmful to the measure it tested, so the evidence favors the low end of these ranges.

Preparations

King's notes that rosemary yields its properties to water or spirits, but more fully to alcohol.¹ The volatile oil and rosmarinic acid come out in hot water. Carnosic acid and carnosol come out in alcohol and oil. Match the preparation to the goal.

Covered infusion. One to two teaspoons of dried leaf, or a 3-inch fresh sprig, per cup of just-boiled water. Cover and steep 10 to 15 minutes.⁷ The lid keeps the volatile oil in the cup. This is the preparation for digestion, a foggy head, and a warming winter tea. Rosemary blends well with peppermint and lemon balm, which balance its strong flavor.
Tincture. 1:5 in 40 percent alcohol per Hoffmann;⁷ a higher proof pulls more of the fat-soluble diterpenes. Tincture is the practical way to include rosemary in a circulatory or nervine formula at small doses.
Infused oil. Dried leaf steeped in olive or jojoba oil for several weeks, then strained. This carries carnosic acid and the volatile oil and is the base for scalp oils, salves, and massage oils for stiff joints. It is not the same thing as the essential oil.
Hair rinse and salt spray. A strong infusion, cooled, poured over the hair after washing and left in. Grieve's version added borax;⁴ a splash of apple cider vinegar does the same job of cutting residue. For a leave-in styling version, my rosemary-infused salt spray recipe combines the infusion with pink Himalayan salt for texture. The hair trial used the essential oil, which is a stronger preparation, so a rinse or spray should be expected to do less.
Bath. The EMA monograph's 50 g decocted in a liter of water and added to a warm bath, 2 to 3 times a week, for tired muscles and cold extremities.⁶
Culinary. Fresh or dried leaf with roasted vegetables, meat, bread, and beans. Daily culinary use delivers a low dose in the range the memory trial found helpful, along with fat, which improves extraction of the diterpenes.
Essential oil. For inhalation and, diluted, on the skin. Not for internal use. See Safety.

Growing Your Own Rosemary

Rosemary is one of the easiest medicinal herbs to grow in the United States, and one of the easiest to kill with too much care. It comes from stony, dry Mediterranean hillsides and wants those conditions reproduced: full sun, lean soil, and fast drainage. Most losses come from wet roots, not cold.

Sun and soil. University of Maryland Extension recommends full sun and well-drained soil with a pH between 6.5 and 7.0.¹³ Avoid heavy clay. In the ground, plant on a slight mound or in a raised bed. In pots, use a cactus mix or a standard potting mix with about a third coarse perlite or grit added. Skip peat-heavy mixes, which hold water and push the pH down.
Watering. Toronto Master Gardeners advise letting the soil become nearly dry between waterings and never leaving the plant waterlogged.¹⁴ Water deeply, let the excess run out, and empty the saucer. Rosemary does not wilt when overwatered. The needles stay upright while the roots rot, and the plant fails suddenly.
Hardiness. In the ground, rosemary is a reliable perennial in roughly USDA zones 8 to 10. In zone 7 it may survive against a south-facing wall with mulch. Cultivars sold as cold-hardy, 'Arp' being the most widely available, tolerate more cold than the standard type. Here in Missoula (zone 5b) it is a container plant that comes indoors for winter.
Containers. Use a pot with drainage holes, ideally unglazed terracotta, which breathes. Toronto Master Gardeners note that digging a rosemary out of a bed to pot it up rarely works, so a plant you intend to overwinter should be container-grown from the start.¹⁴ Repot every two or three years in spring, one size up.
Overwintering indoors. Bring the pot in before the first hard frost. University of Wisconsin Extension recommends a cool, bright spot under 65°F, away from heat registers and radiators, since warm dry indoor air dries out the needles.¹⁵ A south or west window with at least 6 hours of sun, or a grow light, is enough. Water only when the top two inches are dry. Good air circulation and watering the soil rather than the leaves help prevent the powdery mildew that often shows up on indoor rosemary.¹⁴ In spring, after frost danger passes, move it outside gradually over a week.
Feeding. Light. Rosemary in the ground usually needs no fertilizer. For containers, Toronto Master Gardeners suggest a balanced fertilizer after flowering, paired with a trim to keep the plant bushy.¹⁴ Too much nitrogen produces soft growth that attracts pests.
Propagation. Cuttings are the practical route. University of Maryland notes seed can be slow to germinate, and cuttings root quickly when taken in spring during active growth.¹³ Take 4-inch tips of soft new growth, strip the lower needles, and root them in damp perlite or sand in bright shade. Expect some to fail, so take twice as many as you need.
Harvest and drying. Cut sprigs any time during the growing season, taking no more than a third of the plant at once. Dry the sprigs whole in a warm, dark place with airflow, then strip the needles into a jar. Dried rosemary holds its oil far better on the stem than as crushed leaf, so strip only what you need.

Safety, Contraindications, and Interactions

None of the following is medical advice. These are documented cautions from named sources, offered for education. Decisions about medications, pregnancy, and health conditions belong with you and your trusted healthcare provider.

Culinary rosemary has a long safety record. The cautions below apply to therapeutic doses and to the essential oil.

Pregnancy. King's and Cook both record rosemary as an emmenagogue.¹³ Commission E lists pregnancy as a contraindication for the leaf,⁵ and the EMA monograph states that safety in pregnancy and lactation has not been established and does not recommend use.⁶ Culinary amounts are not the concern. Therapeutic doses and the essential oil are.
Essential oil taken internally. The oil concentrates camphor and 1,8-cineole. The 1918 U.S. Dispensatory records a fatal poisoning from oil of rosemary and gives an internal dose of only 3 to 6 minims.² Camphor-rich oils are also on the list of plant oils linked to seizures in susceptible people. I do not use rosemary essential oil internally and I do not recommend it. Diluted on the skin and inhaled are the appropriate routes.
Iron absorption. A human study found a rosemary extract reduced nonheme iron absorption from a meal by 21 percent.¹² People with low iron, and anyone taking iron supplements, may want to keep rosemary tea and iron a couple of hours apart and discuss it with their provider. The effect of ordinary culinary use has not been measured.
Gallbladder and liver conditions. The EMA monograph lists bile duct obstruction, cholangitis, liver disease, gallstones, and other biliary disorders as conditions that require medical supervision before oral use.⁶ Rosemary stimulates bile flow, which is the reason for the caution.
Skin reactions. Contact dermatitis is the one adverse effect the EMA monograph lists, at an unknown frequency.⁶ Do not apply rosemary to broken or irritated skin, and patch-test any scalp oil first.
Children. The EMA does not recommend rosemary as a medicine in children under 12 because there is no adequate data.⁶ Food use is fine.
High doses. The one human dose-ranging trial found 6,000 mg of leaf powder impaired memory speed in older adults.⁹ Large amounts are also reported to irritate the stomach and gut. Keep doses at the low end of the ranges above.
Hot bath caution. The EMA advises people with high blood pressure to use a full hot rosemary bath with care, and anyone with heart or kidney failure to consult a doctor first.⁶
Drug interactions. The EMA monograph reports none.⁶ Some reference sites list theoretical interactions with anticoagulants, blood pressure medication, and diuretics based on laboratory or animal data. No human interaction has been documented. If you take medication with a narrow dosing window, involve your prescriber before using rosemary at therapeutic doses.
Hot constitutions. Rosemary is warming and drying. People who run hot, with flushing, irritability, or dry irritated tissue, tend to tolerate it poorly at higher doses.

Frequently Asked Questions

Does rosemary help hair grow?

One trial found rosemary essential oil on the scalp matched 2 percent minoxidil for hair count over six months, with less itching, in people with pattern hair loss. It had no placebo group, so it does not show rosemary beats doing nothing. Traditional sources used a leaf infusion as a hair rinse for dandruff and scalp health. For the full picture, including nutrition and other herbs, read Herbs and Supplements for Healthy Hair and Faster Growth. Hair loss with a sudden onset or patchy pattern deserves a medical workup.

How do I make rosemary water for my hair?

Simmer a handful of fresh or dried rosemary in water, cool, strain, and use it as a rinse or in a spray bottle. My rosemary salt spray recipe walks through a leave-in version with pink Himalayan salt for texture and optional aloe or jojoba. Keep it in the fridge if your house runs warm.

Is rosemary good for memory?

The tradition says yes, and two small trials point the same direction at low doses: 750 mg of leaf powder improved memory speed in older adults, and 500 mg twice daily improved self-reported memory in students. High doses did the opposite in the older adults. Treat rosemary as supportive, not as a treatment for memory loss.

Can I drink rosemary tea every day?

Regulatory sources give a daily leaf dose of 2 to 6 grams, which is one to three cups of tea, for adults who are not pregnant. The EMA suggests checking with a practitioner if digestive symptoms last more than two weeks. If you have low iron, separate the tea from iron-rich meals or supplements.

Can I take rosemary while pregnant?

Cooking with it is fine. Therapeutic doses and the essential oil are not recommended by Commission E or the EMA because the plant has a traditional history as an emmenagogue and there is no safety data. Bring the question to your midwife or doctor.

Is it safe to ingest rosemary essential oil?

No. The oil concentrates camphor and cineole, and historical pharmacy texts record a fatal poisoning. Use the whole leaf as tea or tincture for internal use. Reserve the oil for inhalation and diluted skin use.

Why is my rosemary plant dying?

Wet roots, almost every time. Rosemary needs fast-draining soil and should dry out between waterings. Indoors, add dry heated air and low light to the list. See the Growing section above for the fixes.

Is rosemary a type of sage?

Since 2017, yes. DNA evidence placed rosemary inside the genus Salvia, so its accepted name is Salvia rosmarinus. Most labels still use Rosmarinus officinalis. Both names mean the same plant.

Keep reading

Rosemary Salt Hair Spray Recipe
Herbs and Supplements for Healthy Hair and Faster Growth
Sage — rosemary's closest relative in this library
Peppermint — a cooling mint-family partner for tea blends

Researched and maintained by Ivy Ham

Certified clinical herbalist based in Missoula, Montana, with training in Western herbalism, Ayurveda, and Traditional Chinese Medicine. This monograph is updated as new research and sources become available. Last updated September 2026. About Ivy

Sources

Felter HW, Lloyd JU. Rosmarinus (Rosemary). King's American Dispensatory, 1898. Public domain, hosted at Henriette's Herbal.
Remington JP, Wood HC, eds. Oleum Rosmarini (Oil of Rosemary). The Dispensatory of the United States of America, 1918. Public domain, hosted at Henriette's Herbal.
Cook WH. Rosmarinus officinalis. The Physiomedical Dispensatory, 1869. Public domain, hosted at Henriette's Herbal.
Grieve M. Rosemary. A Modern Herbal, 1931. Public domain, hosted at botanical.com.
German Commission E monograph, Rosmarini folium (Rosemary leaf). In: Blumenthal M, ed. The Complete German Commission E Monographs. American Botanical Council, 1998.
European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Rosmarinus officinalis L., folium. EMA/HMPC/513940/2021, revision 1, adopted 29 May 2024.
Hoffmann D. Medical Herbalism: The Science and Practice of Herbal Medicine (affiliate link). Healing Arts Press, 2003.
Drew BT, González-Gallegos JG, Xiang CL, et al. Salvia united: The greatest good for the greatest number. Taxon. 2017;66(1):133-145. DOI: 10.12705/661.7.
Pengelly A, Snow J, Mills SY, Scholey A, Wesnes K, Butler LR. Short-term study on the effects of rosemary on cognitive function in an elderly population. Journal of Medicinal Food. 2012;15(1):10-17. DOI: 10.1089/jmf.2011.0005.
Nematolahi P, Mehrabani M, Karami-Mohajeri S, Dabaghzadeh F. Effects of Rosmarinus officinalis L. on memory performance, anxiety, depression, and sleep quality in university students: a randomized clinical trial. Complementary Therapies in Clinical Practice. 2018;30:24-28. DOI: 10.1016/j.ctcp.2017.12.007.
Panahi Y, Taghizadeh M, Marzony ET, Sahebkar A. Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial. Skinmed. 2015;13(1):15-21.
Samman S, Sandström B, Toft MB, et al. Green tea or rosemary extract added to foods reduces nonheme-iron absorption. American Journal of Clinical Nutrition. 2001;73(3):607-612. Funded by the Danish Ministry of Education.
University of Maryland Extension. Rosemary. Home and Garden Information Center.
Toronto Master Gardeners. How to Grow Rosemary: A Toronto Master Gardeners Guide.
University of Wisconsin-Madison Extension, Kenosha County. Holiday Rosemary. December 2020.

Meet the Other Salvias

Rosemary joined the genus Salvia in 2017. Salvia holds nearly a thousand species in the mint family (Lamiaceae), and two others have entries in this library. Neither is interchangeable with rosemary.

Garden Sage

Salvia officinalis

Part used: leaf. Also called common sage.

The astringent, drying kitchen sage. Traditionally used as a mouth and throat rinse and to reduce excess sweating. Contains thujone, so its safety section covers dose limits.

Read the sage monograph

Red Sage (Dan Shen)

Salvia miltiorrhiza

Part used: root. Also called Chinese sage.

A Chinese medicine root, not a culinary herb. Traditionally used to move blood and clear heat, and studied for cardiovascular support. Carries a documented warfarin interaction.

Read the red sage monograph

Rosemary

Key Takeaways

Botany and the Name Change

Energetics

Constituents