Scientific Name(s): Rosmarinus officinalis L.
Common Name(s): Anthos, Old man, Rosemary
Medically reviewed by Drugs.com. Last updated on Jun 20, 2023.
Limited clinical studies support traditional uses of rosemary as an antibacterial, anti-inflammatory, and spasmolytic. In addition to the well-established culinary uses of rosemary, potential dermatologic, CNS, and antioxidant applications have also been studied. However, limited clinical data exist to recommend rosemary for any indication.
Various rosemary preparations have been used for various indications; however, clinical evidence is lacking to provide dosing recommendations for any indication. Traditional uses include 2 g of chopped leaf infused in water, or 2 to 4 g of the shoot. Other decoctions have been described. Low oral doses (750 mg) of dried rosemary leaf powder were used in a clinical study for improvement of memory speed in elderly patients, while higher doses (6 g) impaired memory speed. Studies evaluating rosemary aromatherapy used 3 to 4 drops for inhalation.
Contraindications have not been identified.
Rosemary has generally recognized as safe (GRAS) status when used as food. Dosages above those found in food should be avoided because safety and efficacy are unproven. Rosemary may have emmenagogic and abortifacient effects.
None well documented.
Dermatitis, allergy, and photosensitivity to rosemary extracts or oil have been reported. Although case reports of seizures due to rosemary are lacking, the potential for toxicity exists, possibly due to the high camphor content found in rosemary oil.
Information is limited. As with most essential oils, ingestion of large amounts can be toxic.
- Lamiaceae (mint)
R. officinalis grows as a small evergreen shrub with thick, aromatic leaves. 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, with more than 20 varieties described. R. officinalis should not be confused with bog rosemary (Andromeda polifolia) or marsh rosemary (Rhododendron tomentosum) from the heath family.Begum 2013, Duke 2002, Khan 2010, USDA 2020
Rosemary is a widely used culinary spice or flavoring agent in foods. Rosemary was traditionally suggested as growing only in gardens of households where the "mistress" is truly the "master."Tyler 1987 Historical reports regarding therapeutic use of rosemary plant are available.Selmi 1967, Zimmermann 1980 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.Tyler 1987 Rosemary extracts are commonly found in cosmetics, and a lotion of the plant has been said to stimulate hair growth and prevent baldness.(Duke 2002 In the Complete German Commission E Monographs, rosemary leaf is approved for internal use in dyspeptic complaints and for external use as supportive therapy in rheumatic diseases.Blumenthall 2000 Rosemary, one of the oldest known medicinal herbs, was used centuries ago to enhance mental function and memory.Duke 2002
Rosemary consists of a wide variety of volatile and aromatic components. About 150 chemical compounds have been identified in essential oils from R. officinalis, the most frequently reported molecules being 1,8-cineole, alpha-pinene, and camphor.Borges 2019 The plant's leaves contain 0.5% to 2.5% of volatile oil, with major components including monoterpene hydrocarbons (alpha- and beta-pinene), camphene, limonene, camphor (10% to 20%), borneol, cineole, linalool, and verbinol. Flavonoids in the plant include diosmetin, diosmin, genkwanin, luteolin, hispidulin, and apigenin.Duke 1992, Khan 2010 Other terpenoid constituents in rosemary include triterpenes, such as oleanolic and ursolic acids, and diterpenes, such as carnosol.Duke 1992 Phenols in rosemary include caffeic, chlorogenic, labiatic, neochlorogenic, rosmarinic, and salicylic acids.Begum 2013, Duke 1992, Ulbricht 2010
Uses and Pharmacology
The active pharmacological compounds related to rosemary have anti-inflammatory, chemopreventive, antiproliferative, antimicrobial, and neuroprotective effects, as well as decrease risks related to obesity, diabetes, and metabolic syndrome, among others.de Oliveira 2019, Sánchez-Camargo 2017 A review suggests that the anti-inflammatory activity of rosemary essential oil occurs mainly through inhibition of nuclear factor kappa B transcription and suppression of the arachidonic acid cascade. Its antioxidant activity also aids by preventing injury caused by the reactive species of inflammation.Borges 2019 Rosemary's spasmolytic effect has been attributed to antagonism of acetylcholine, with borneol considered the most active component of the oil.Barnes 2007 Alpha-pinenes and beta-pinenes exhibit spasmogenic activity towards smooth muscle but have no effect on cardiac muscle.Barnes 2007
A randomized, controlled, single-blind study in healthy individuals (N=106) revealed no changes in any spirometry measures evaluated following inhalation of rosemary essential oil.Koteles 2018 However, in a small double-blind, placebo-controlled clinical study, patients with bronchial asthma (N=16) were treated with 1,8-cineole (a major component of rosemary oil). Twelve patients experienced improvement in this inflammatory-induced condition.Borges 2019
In vitro data
In terms of anticonvulsant activity, in vitro human embryonic kidney (HEK) cells were exposed to rosemary oil at a concentration of 0.054 mg/mL. Rosemary essential oil inhibited CaV3.2 T-type calcium channels, and rosmarinic acid was determined to be the active component responsible for this activity.Bahr 2019
In vitro and in vivo data
Evidence of antigenotoxic effects of rosemary and its phytochemicals has been demonstrated in some in vitro and in vivo studies.López-Romero 2018
In rabbits, rosmarinic acid (20 mg/kg intravenously) decreased endotoxin-induced complement activation, formation of prostacyclin, thrombocytopenia, and the release of thromboxane A2.Barnes 2007, Bult 1985 The application of topical rosmarinic acid (5%) to rhesus monkeys reduced gingival plaque indices when compared with placebo.Barnes 2007
In a randomized, controlled, open and double-blind trial in 110 volunteers, a rosemary-based toothpaste effectively treated gingival bleeding and reduced bacterial plaque when compared with conventional toothpaste.Valones 2019
Small-scale clinical trials have evaluated the hypolipidemic effects of dried rosemary leaf powder (2, 5, or 10 g/day for 2 months). In a study of patients with dyslipidemia, rosemary decreased fasting plasma glucose, total cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) by ameliorating oxidant-antioxidant content. In addition, rosemary powder (3 g/day for 4 weeks) ameliorated the lipid profile and blood glucose in a study of patients with type 2 diabetes.Farkhondeh 2019
Antimicrobial and antiviral effects
Animal and in vitro data
Rosemary oil has in vitro antibacterial, antifungal, and antiviral properties.Begum 2013, Duke 1992, Ulbricht 2010 Rosemary essential oil was found to exhibit significant antifungal effects against Aspergillus flavus in a dose-dependent manner. Compared to 100% growth inhibition with nystatin, rosemary essential oil inhibited growth ranging from 15.3% at concentrations of 250 mcg/mL up to 93.2% at 2,000 mcg/mL. The production of aflatoxins was inhibited at concentrations below those that were fungistatic.da Silva Bomfim 2019 Carnosic acid, isolated from rosemary, exhibited strong in vitro inhibitory effects against HIV protease in one study.Paris 1993 In addition, carnosol and ursolic acid have inhibited a range of food spoilage microbes; this activity was comparable to known antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).Barnes 2007 Hexane and ethyl acetate fractions from the R. officinalis flower exhibited remarkable in vitro antibacterial, antioxidant, anti-inflammatory, and analgesic activities, possibly due to their polyphenol content.Karadağ 2019
Clinical data regarding the use of rosemary oil or extracts for antibacterial or antifungal use are limited. A report on the use of rosemary to treat head lice found it to be ineffective, although rosemary has been traditionally used for this purpose.Veal 1996
Animal data and in vitro data
Antioxidant activity has been described for rosemary, with the chemical constituents carnosol and carnosic acid accounting for the majority of the antioxidant properties.Aruoma 1992, Begum 2013, Roohbakhsh 2020, Ulbricht 2010 Lipophilic and hydrophobic fractions of rosemary showed activity by inhibiting superoxide anion production in the xanthine/xanthine oxidase system.Barnes 2007
Although there are no clinical data regarding antioxidant use of rosemary oil or extracts, antioxidant activity may be the underlying mechanism of action for other pharmacological effects.
In vitro data
Antispasmodic action of rosemary oil in isolated guinea pig smooth muscle and cardiac tissue has been described.Barnes 2007
In vitro and animal studies have demonstrated anticancer effects of rosemary extracts (especially carnosol and carnosic, ursolic, and rosemarinic acids), with a variety of mechanisms of action proposed, including induction of apoptosis, radical scavenging, and inhibition of tumorigenesis.Ngo 2011
Dietary supplementation in laboratory animals with rosemary extract 1% resulted in a significant (47%) decrease in the incidence of experimentally induced mammary tumors compared with controls.Singletary 1991, Singletary 1997 The extract enhanced activities of enzymes that detoxify reactive substances in mouse liver and stomach.Singletary 1997 Skin tumors in mice were inhibited by application of rosemary extract to the area.Huang 1994 Overall, rosemary extract, carnosic acid, and rosmarinic acid have been shown to have various potent and effective anticancer properties. However, more systematic studies are required in animals before clinical studies are initiated.Moore 2016
Animal and in vitro data
A neuroprotective effect was demonstrated in vitro, with rosemary extract enhancing the synthesis of nerve growth factor in T98G human glioblastoma cells.Ulbricht 2010 In older studies in rodents, administration or inhalation of the oil affected the cerebral cortex, decreased immobility duration (antidepressant-like effects), and improved endurance tests.Ulbricht 2010
Rosemary diterpenes have also been shown to inhibit neuronal cell death induced by a variety of agents, both in vitro and in vivo.Habtemariam 2016 In a scopolamine-induced dementia rat model of Alzheimer disease, the memory enhancing effects of rosemary extract (200 mg/kg orally) were linked with a direct effect on acetyl cholinesterase activity. While mRNA expression of butyrylcholinesterase in the cortex was inhibited, its expression in the hippocampus was enhanced by rosemary extract.Ozarowski 2013
In at least 2 small, randomized controlled trials examining the aromatherapeutic effects of rosemary oil, improved recall was demonstrated.Burnett 2004, Moss 2003 Although experimental studies have shown decreased anxiety and increased alertness with rosemary oil inhalation, additional studies are needed.Ulbricht 2010 One study demonstrated improved speed but not accuracy in computing mathematical calculations when 40 adults were given rosemary aromatherapy.Diego 1998, Ulbricht 2010 Two studies have suggested that the effects of rosemary essential oil in managing pain may have been due to altered perceptions rather than direct analgesia.Buckle 1999, Gedney 2004
In a crossover study of 28 elderly participants, low-dose rosemary (750 mg) improved measures of memory speed, whereas higher doses (6 g) impaired responses.Pengelly 2012 A study of healthy young adults with olfactory senses blocked and administered rosemary 1.7 g orally showed no effect on motivation to perform cognitive tasks.Lindheimer 2013
In a double-blind, randomized controlled trial, students (N=68) were randomized to receive 500 mg capsules of rosemary or placebo twice daily for 1 month. Prospective and retrospective memory performance, depression, anxiety, and sleep quality of the students were measured at baseline and after 1 month. The scores of all the scales and subscales, except for sleep latency and sleep duration components, were significantly decreased in the rosemary group compared with the control group after 1 month. It was concluded that rosemary, when used at a safe dose, could be used to boost prospective and retrospective memory, reduce anxiety and depression, and improve sleep quality in university students.Nematolahi 2018
A study in mice demonstrated that rosemary leaf extract applied topically improved hair growth, possibly via inhibition of testosterone reductase.Murata 2013
In a randomized clinical trial evaluating rosemary oil and minoxidil 2% in patients with androgenetic alopecia (N=100), no change in outcome measures at 3 months occurred; however, at 6 months both groups showed increased hair counts from baseline on photographic assessment. Effects of rosemary oil were reported to be equivalent to those of minoxidil.Panahi 2015 Rosemary acts by improving blood circulation and vascularity, helping the regeneration of follicles similar to the effect provided by minoxidil.Dhariwala 2019
Animal and in vitro data
Rosemary extract and rosemary extract polyphenols such as carnosic acid and rosmarinic acid have shown insulin-like effects in insulin target cells in vitro and have exerted antidiabetic effects in different animal models of type 2 diabetes mellitus in vivo.Naimi 2017
A clinical study evaluating rosemary in combination with polyunsaturated fatty acids in children with type 1 diabetes as a strategy to improve oxidative damage showed equivocal results.Balderas 2010 Additional clinical trials are warranted to examine the effects of rosemary extract and its polyphenolic constituents directly in humans.Naimi 2017
Animal and in vitro data
Immunomodulatory effects of rosemary extract have been demonstrated in a rat model of peritoneal adhesion, particularly at concentrations of 2% and 4%. Peritoneal adhesions as well as interleukin (IL)-6, IL-1beta, tumor necrosis factor (TNF)-alpha, transforming growth factor-beta1, and vascular endothelial growth factor were all significantly reduced with rosemary extract compared to control/vehicle groups.Roohbakhsh 2020 In bone marrow mast cells, rosemary leaf extract inhibited early allergic signaling pathway activation (eg, NF-kappaB) as well as significantly impaired mRNA for several pro-inflammatory cytokines and chemokines (ie, IL-6, IL-13, TNF) thereby reducing downstream production and release. Consequently, the resulting activation of mast cell degranulation was also significantly inhibited.Yousef 2020
Various rosemary preparations have been used for various indications; however, clinical evidence is lacking to provide dosing recommendations for any indication. Traditional uses include 2 g of chopped leaf infused in water, or 2 to 4 g of the shoot. Other decoctions have been described.Duke 2002
Low oral doses (750 mg) of dried rosemary leaf powder were used in a clinical study for improvement of memory speed in elderly patients, while higher doses (6 g) impaired memory speed.Pengelly 2012
Pregnancy / Lactation
Rosemary has GRAS status when used as food. Dosages above those found in food should be avoided because safety and efficacy are unproven. Rosemary inhibited uterotropic actions of estradiol and estrone in rodent studies.Zhu 1998 Rosemary may have emmenagogic and abortifacient effects, although evidence is weak.Duke 2002, Ernst 2002
None well documented.
Topical application of essential oils can cause seizures in susceptible individuals with epilepsy. Camphor content in rosemary essential oil was thought to be the cause of a seizure in a patient with a history of epilepsy; the patient had not experienced a seizure in 8 years but experienced a breakthrough (relapse) seizure after a massage with a topical blend of sea fennel, maritime pine, sea buckthorn, and rosemary essential oils.Bahr 2019
Information regarding toxicity is limited. As with most essential oils, ingestion of large amounts of rosemary essential oil can be toxic.Duke 2002 Antigonadotrophic activity has been described in mice,Newall 1996 and an anti-implantation effect has also been described in rat experimentation.Lemonica 1996 Rosemary oil contains 20% to 50% camphor. Camphor causes epileptiform convulsions when taken orally in sufficient quantity.Barnes 2007
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