Medically reviewed on June 7, 2018
What is Rosemary?
Rosemary 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 now is cultivated worldwide. Other types of rosemary include bog rosemary (Andromeda species) and wild or marsh rosemary (Ledum palustre).
Rosemary also is known as old man.
What is it used for?
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." The plant has been used in traditional medicine for its astringent, tonic, carminative, antispasmodic, and diaphoretic properties. Rosemary is one of the oldest known medicinal herbs, used centuries ago to enhance mental function and memory. Extracts and the volatile oil have been used to promote menstrual flow and as abortives. Rosemary extracts commonly are found as cosmetic ingredients and a lotion of the plant is said to stimulate hair growth and prevent baldness.
Rosemary is a known antimicrobial agent. The powdered leaves are used as an effective natural flea and tick repellent. Rosemary oil possesses marked antibacterial, antifungal, and antiviral properties. Rosemary oil was found to be most active against "meat-spoiling" bacteria. A report on the use of rosemary to treat head lice found it to be ineffective.
There are numerous reports available evaluating rosemary's anticancer effects. The extract induces an anticarcinogenic enzyme. Other anticancer mechanisms include polyphenol constituents that inhibit metabolic activation of procarcinogens. Rosemary has been reported to decrease capillary permeability and fragility. The plant may have spasmolytic actions, liver, and immune effects. Rosemary also may reverse headaches, reduce stress, and aid in asthma and bronchitis treatment. Rosemary also is used in aromatherapy for chronic pain treatment. Several reports exist concerning rosemary's antioxidative actions. Rosemary antioxidants have less scavenging potential than green tea polyphenols, but have more potential than vitamin E.
While research is promising, more clinical testing will need to be done to validate all the medicinal uses of rosemary.
What is the recommended dosage?
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 when used as food. Avoid dosages above those found in food because safety and efficacy are unproven. Known to have emmenagogue (to stimulate menstrual flow) and abortive effects.
None well documented.
Ingestion of large quantities of rosemary may 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 also is an abortive.
Ingestion of large quantities of the oil may be associated with toxicity.