Rosemary (Rosmarinus officinalis) is one of those plants that seems to belong to more than one world at once. It grows in ordinary gardens, yet it turns up in old herbals, in funeral customs, in perfumery ledgers and in modern safety reviews. This article gathers what the sources in our library say about it — the traditional, the historical and the scientific — and keeps each in its own lane.

What the tradition says

The Complete Herbal places rosemary under the governance of the Sun and the celestial Ram, and describes it as warming and comforting, dry in the second degree. In that text rosemary is written about in relation to cold conditions of the head, stomach, liver and belly, and a decoction in wine is mentioned in connection with cold diseases of the head and brain, including giddiness and drowsiness. The same herbalist wrote that rosemary helps a weak memory and quickens the senses, and that burning it in houses and chambers corrects the air. Rosemary flowers, in that tradition, were used for the head, the heart, the stomach and the joints, and were also said to dry the heart. Elsewhere in the old literature, rosemary was used to provoke the terms and to ease pain. The Complete Herbal also records that Dioscorides and Galen described a water decoction of rosemary followed by exercise in connection with yellow jaundice.

Historical context

The Old English Herbals tells a story worth knowing: a manuscript on the virtues of rosemary was sent by the Countess of Hainault to her daughter Philippa, Queen of England, and this manuscript is the original of the poetical discourse on rosemary in Banckes's Herbal. Tradition holds that Queen Philippa's mother sent the first rosemary plants to England, and a translator named Danyel Bain wrote that rosemary was unknown in England until that gift. The same manuscript is described as the oldest in which many beliefs about rosemary that still survive in England are found. There is also a tradition that when rosemary reaches thirty-three years of age it increases in breadth but not in height.

Banckes's Herbal contains some of the most charming entries: rosemary flowers powdered and bound to the right arm in linen to make a person light and merry; leaves under the bed to deliver a person from evil dreams; leaves in wine to keep it from sourness; a white wine decoction used to wash the face and brows; rosemary wood burned to coals and rubbed on the teeth; and smelling rosemary often, or keeping a box of rosemary wood to smell, to preserve youth. It also listed a drink of rosemary leaves boiled in white wine in connection with cough. In later English practice, rosemary was placed with the corpse in the coffin and sprigs were given to mourners to throw into the grave, and it was carried at funerals as a preservative against pestilential disorders. Smelling rosemary was thought to defend against morbid effluvia from corpses. Rosemary leaves used in bathings, ointments or oil were recorded in connection with cold, benumbed joints, sinews or members.

In perfumery, distillation of rosemary yields a thin, limpid otto with the plant's characteristic odour, more aromatic than sweet. Otto of rosemary was extensively used, especially with other ottos for scenting soap. Rosemary oil was the leading ingredient in Hungary water and was considered indispensable to eau de Cologne. A historical Hungary water recipe combined rectified alcohol with two ounces of English rosemary otto and other oils, and Hungary water is said to be named after a Hungarian queen who reportedly benefited from a bath containing it at seventy-five. The book claimed that rosemary in Hungary water or eau de Cologne excites the mind to vigorous action when inhaled, benefiting speakers. Perfumes containing rosemary were universally said to be refreshing.

The ingredient and the practice

Rosemary is Rosmarinus officinalis, an evergreen shrub whose flowers appear in April and May, and sometimes again in August. The plant contains alkaloids, phenolic acids, saponins, tannins, diterpenes, flavonoids and essential oils. Leaves and tops yield a volatile oil, though the flowers contain more. The essential oil contains around 150 phytochemicals, among them rosmarinic acid, camphor, α-pinene, caffeic acid, ursolic acid, betulinic acid, carnosic acid and carnosol, with camphor making up roughly 10–20%. One hundredweight of fresh herb yields about twenty-four ounces of oil. Forms used include fresh or dried leaf, the flowers, the essential oil (otto), rosemary water from distillation, and historical preparations such as hair washes and astringent extracts.

Traditional associations

• Memory and the mind — the old herbals link rosemary with a weak memory and quickened senses, and the ancients thought it refreshed the memory and comforted the brain.
• Smoke and air — burning rosemary in houses and chambers was said to correct the air.
• Mourning — sprigs placed with the dead and thrown into the grave by mourners.
• Perfumery — a leading ingredient in Hungary water and indispensable to eau de Cologne.
• Refreshment — perfumes containing rosemary were universally said to be refreshing.

How different traditions vary

Sources disagree about rosemary's safety profile. One review states that rosemary is generally considered safe for consumption and topical application, while also noting that allergic reactions and dermatitis have been reported in some individuals. The same review raises the possibility of toxicological effects on the liver and kidney, including atrophic and degenerative changes, and suggests rosemary may induce reproductive toxicity by decreasing spermatogenesis, testosterone, sperm density and motility, and might trigger genotoxicity and fetal anomalies; it advises caution with chronic high doses. A 2021 reproductive and developmental toxicity screening study of an acetone rosemary extract found no signs of general toxicity or effects on reproduction in rats, and the highest tested dose was established as the no-observed-adverse-effect level for general and reproductive toxicity. That study did observe dose-related reductions in T4 in Day 13 pups, and noted that further investigation is required to determine their biological relevance. So the picture is not settled: one line of evidence flags possible adverse general and reproductive effects, another reports no observed effects at the highest dose tested.

Practical use

In traditional and perfumery practice, rosemary is most often used by scent and smoke rather than by swallowing. Burning dried rosemary or rosemary wood to scent a room follows the old custom of correcting the air in houses and chambers. A few drops of rosemary essential oil in a diffuser, or on a tissue, carries the refreshing quality that perfumers prized. Historically, rosemary water was made by distilling rosemary free from stalk with water, and it was used in perfumery manufacture. A simple aromatic hair wash was made from rosemary water, rectified spirit and pearlash, tinted with brown colouring.

For topical use, dilute essential oil in a carrier oil before applying to skin, and patch-test first, since allergic reactions and dermatitis have been reported. Rosemary leaves can be added to a bath in the old manner of bathings and ointments. Keep essential oil away from the eyes, and do not take it internally without qualified advice; the safety review specifically advises caution with chronic high doses.

Safety

What is and is not scientifically established

Scientifically, rosemary has been reviewed for antioxidant, anti-inflammatory, antibacterial, anticancer, neuroprotective, cardioprotective and hepatoprotective effects. Those are laboratory and review findings about activity, not evidence that rosemary does anything therapeutic in people. The safety literature is mixed: one review describes rosemary as generally considered safe for consumption and topical application while also listing possible liver, kidney, reproductive and genotoxic concerns at high chronic doses; a 2021 rat study of an acetone extract found no general or reproductive toxicity at the highest dose tested, with T4 reductions in pups of uncertain biological relevance. What is not established is a clear, consistent human safety threshold, and the disagreement between sources is best read as a reason for moderation rather than confidence in either direction.

Questions people ask

Is rosemary safe to use around the home?

The review literature describes rosemary as generally considered safe for consumption and topical application, while noting reported allergic reactions and dermatitis in some people. For aromatic use, dilute essential oil and patch-test first.

Why is rosemary linked with memory?

The Complete Herbal says rosemary helps a weak memory and quickens the senses, and another herbal notes the ancients thought it refreshed the memory and comforted the brain. This is traditional attribution, not a scientific finding.

Do the sources agree on rosemary's reproductive safety?

No. One review raises the possibility of reproductive toxicity and fetal anomalies, while a 2021 rat study of an acetone extract found no effects on reproduction and set a no-observed-adverse-effect level at the highest dose tested. The T4 reductions seen in pups need further investigation.

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• Try the free INFLUANCE tool

Sources

• Toxicity and safety of rosemary (Rosmarinus officinalis): a comprehensive review. — Ghasemzadeh Rahbardar M; Hosseinzadeh H (research abstract)
• Reproductive and developmental toxicity screening study of an acetone extract of rosemary. — Phipps KR; Danielewska-Nikiel B; Mushonganono J (research abstract)
• Rosemary — Wikipedia — Wikipedia contributors
• The Complete Herbal — Nicholas Culpeper (historical text)
• The Old English Herbals — Eleanour Sinclair Rohde (historical text)
• The Art of Perfumery, and Methods of Obtaining the Odors of Plants — G. W. Septimus Piesse (historical text)
• Herbal simples approved for modern uses of cure — William Thomas Fernie (historical text)

Knowledge version 0.4.0 of the JARVIS Spiritual Herbs, Oils & Traditional Practice capability. Traditional and spiritual practice only — not medical advice.