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Medically reviewed on Jun 18, 2018

Scientific Name(s): Rosmarinus officinalis L. Family: Lamiaceae (mints)

Common Name(s): Rosemary , old man


Rosemary has been reported to decrease capillary permeability and fragility. Extracts have been used in insect repellents. The plant may have anticancer properties and has spasmolytic actions, liver and immune effects, and other various actions from asthma treatment to aromatherapy. It has antimicrobial actions against a variety of bacteria, fungi, mold, and viruses.


Rosemary leaf was approved for dyspepsia, high blood pressure, and rheumatism by the German Commission E at doses of 4 to 6 g/day. The essential oil has been used at doses of 0.1 to 1 mL.


Contraindications have not yet been identified.


Generally recognized as safe or used as food. Avoid dosages above those found in food because safety and efficacy are unproven. Known to have emmenagogue and abortifacient effects.


None well documented.

Adverse Reactions

Ingestion of large quantities of rosemary can result in stomach and intestinal irritation and kidney damage. Allergic contact dermatitis has been associated with the plant, but rosemary is not generally considered to be a human skin sensitizer. Rosemary's constituents, monoterpene ketones, are convulsants, and have caused seizures in large doses. Rosemary is also an abortifacient.


Ingestion of large quantities of the oil can be associated with toxicity.


Rosemary grows as a small evergreen shrub with thick aromatic leaves. 1 The plant has small pale-blue flowers that bloom in late winter and early spring. Although rosemary is native to the Mediterranean, it is now cultivated worldwide. 2 , 3 Other types of rosemary include bog rosemary ( Andromeda species) and wild or marsh rosemary ( Ledum palustre L.).


Rosemary is a widely used culinary spice. Tradition holds that rosemary will grow only in gardens of households where the “mistress” is truly the “master.” 4 The plant has been used in traditional medicine for its astringent, tonic, carminative, antispasmodic, and diaphoretic properties. Extracts and the volatile oil have been used to promote menstrual flow and as abortifacients. 4 , 5 Rosemary extracts are commonly found as cosmetic ingredients and a lotion of the plant is said to stimulate hair growth and prevent baldness. 6

Historical reports regarding the therapeutic use of rosemary as a medicinal plant are available. 7 , 8 Rosemary is one of the oldest known medicinal herbs, having been used centuries ago to enhance mental function and memory. 9


The leaves contain 0.5% to 2.5% of volatile oil. The major components of the oil include monoterpene hydrocarbons (alpha and beta-pinene), camphene, limonene, camphor (10% to 20%), borneol, cineole, linalool, and verbinol. Rosemary contains a wide variety of volatile and aromatic components. Flavonoids in the plant include diosmetin, diosmin, genkwanin, luteolin, hispidulin, and apigenin. 1 , 4 , 10 One analysis reports 3 new flavonoid glucuronides, also found in the leaves. 11 Other terpenoid constituents in rosemary include triterpenes oleanolic and ursolic acids and diterpene carnosol. 10 The concentration of phenolic diterpenes in certain commercial rosemary extracts has been determined by HPLC. 12 Phenols in rosemary include caffeic, chlorogenic, labiatic, neochlorogenic, and rosmarinic acids. 10 Rosemary contains high amounts of salicylates. 13

Uses and Pharmacology

Rosemary is a known antimicrobial agent. The powdered leaves are used as an effective natural flea and tick repellent. 14 Rosemary oil possesses marked antibacterial, antifungal, and antiviral properties. 9 , 10 Activity against certain bacteria including Staphylcoccus aureus , S. albus , Vibrio cholerae , Escherichia coli , and Corynebacteria has been observed. 10 Rosemary oil was found to be most active against “meat spoiling” gram-negative (eg, Pseudomonas ) and gram-positive (eg, Lactobacillus ) bacteria in 1 report. 15 The effect of rosemary on Candida albicans has been described. 16 Another report discusses growth inhibition of Aspergillus parasiticus by rosemary oil. 17 However, a report on the use of rosemary to treat head lice found it to be ineffective. 18

There are numerous reports available evaluating rosemary's anticancer effects. The extract induces quinone reductase, an anticarcinogenic enzyme. 19 Other anticancer mechanisms include polyphenol constituents that inhibit metabolic activation of procarcinogens by Phase Ι enzymes (P450), and induction of the detoxification pathway caused by Phase ΙΙ enzymes (glutathione S-transferase). 20

Animal data

Dietary supplementation of laboratory animals with 1% rosemary extract resulted in a 47% decrease in the incidence of experimentally-induced mammary tumors compared to controls. 21 , 22 This extract was found to enhance activities of enzymes that detoxify reactive substances in mouse liver and stomach. 23 Skin tumors in mice have been inhibited by application of rosemary extract to the area. 24

Clinical data

Rosemary increased detoxification of carcinogens in human bronchial epithelial cells as well. 25 Rosemary diterpene, carnosic acid, exhibited strong inhibitory effects against HIV-protease. 26

Several reports exist concerning rosemary's antioxidative actions. 27 , 28 , 29 , 30 , 31 Carnosol and carnosic acid have been reported to account for more than 90% of the antioxidant properties of rosemary extract. Both are powerful inhibitors of lipid peroxidation and are good scavengers of peroxyl radicals. 32 , 33 Antioxidant activity depends directly on concentration of diterpenes such as these. 12 Rosemary antioxidants have less scavenging potential than green tea polyphenols but have more potential than vitamin E. 34

Various reports involving other actions of rosemary include spasmolytic actions in smooth and cardiac muscle, alteration of complement activation, 10 liver effects, 35 immune effects, 36 and aromatherapy for chronic pain treatment. 37 Rosemary may also reverse headaches, reduce stress, and aid in asthma and bronchitis treatment. 9 Rosemary's pharmacology has been reviewed. 38

Other animal studies have shown inhibition of adult respiratory distress syndrome in rabbits, 10 reduction of capillary permeability, 4 and antigonadotrophic activity in mice. 10 Rosemary inhibits uterotropic actions of estradiol and estrone by 35% to 50% vs controls. 39


Rosemary leaf was approved for dyspepsia, high blood pressure, and rheumatism by the German Commission E at doses of 4 to 6 g/day. The essential oil has been used at doses of 0.1 to 1 mL. 40


Generally recognized as safe or used as food. Avoid dosages above those found in food because safety and efficacy are unproven. Known to have emmenagogue and abortifacient effects. 41


None well documented.

Adverse Reactions

Although the oil is used safely as a food flavoring and the whole leaves are used as a potherb and spice, ingestion of large quantities of the oil can be associated with toxicity. 42 Toxicity from the oil is characterized by stomach and intestinal irritation and kidney damage. 4 Although rosemary oil is irritating to rabbit skin, it is not generally considered to be a sensitizer for human skin.

At least 3 case reports concerning toxic seizures associated with rosemary exist. The plant's monoterpene ketones are powerful convulsants with known epileptogenic properties. 43


Preparations containing the oil may cause erythema, and toiletries can cause dermatitis in sensitive individuals. 1 , 6 , 10 Allergic contact dermatitis from rosemary has been reported. 44 A case report discusses contact dermatitis in a 56-year-old man reacting to carnosol, the main constituent in a rosemary preparation. 45

Certain molds may grow on rosemary. 46

A case of occupational asthma caused by rosemary has been reported. 47

Rosemary extract may possess an anti-implantation effect as seen in rat experimentation. 48 The plant is a reported abortifacient, and also affects the menstrual cycle. 10


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24. Huang M, et al. Inhibition of skin tumorigenesis by rosemary and its constituents carnosol and ursolic acid. Cancer Research 1994;54(3):701-08.
25. Offord E, et al. Rosemary components inhibit benzo[a]pyrene-induced genotoxicity in human bronchial cells. Carcinogenesis 1995;16(9):2057-62.
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