Aroma Corner
essential oils at home, with care
Essential oil dictionary: 43 common oils from A to Z
This table covers 43 essential oils you are likely to meet: on a department store shelf in Fukuoka, in a gift box, or at the back of a friend's bathroom cabinet. For each one you get the botanical name, the part of the plant used, how the oil is made, its scent, common home uses and the cautions that matter. If you only read one column, read the last one.
Essential oils are concentrated plant chemicals. Most are pleasant and low risk when diluted and used with some care, but several can burn or sensitise skin, a few react with sunlight, and nearly all of them are poisonous to a small child who drinks from the bottle. None of the oils below should be swallowed, and none of them replaces medical care.
How to read the table
The "part used" and "main method" columns tell you where an oil came from. Most oils are steam distilled. Citrus peel oils are usually cold pressed ("expressed"), which carries over heavier compounds that distillation leaves behind, including some that react with sunlight. Jasmine and other delicate flowers are solvent extracted to make an absolute, and sticky resins such as benzoin are sold as resinoids. Our guide to how essential oils are extracted covers each method.
"Common home uses" describes what people typically do with an oil: a few drops in a diffuser, a diluted massage blend, a bath. It is not a list of proven effects. Research on most oils is thin, and where something is better established the notes below say so.
When a caution says "dilute low", think 1%: about 1 drop of essential oil in 5 ml (one teaspoon) of carrier oil, taking a standard dropper as roughly 20 drops per ml. Everyday body blends for healthy adults sit at 1 to 2%, and the face, older people and anyone with sensitive skin do better at the low end. The dilution chart has drop counts for common bottle sizes. In a bath, oils float on the water and reach the skin undiluted, so mix them first into a tablespoon of carrier oil or an unscented bath dispersant.
Botanical names, and why they matter when you buy
Every plant has a two-part Latin name, the genus and then the species, printed in italics. Common names are loose, and that is where mix-ups start. "Chamomile" on a label could mean either of two different plants with different chemistry, colour and price. "Cedarwood" could be a true cedar (Cedrus) or a juniper sold as Virginian cedarwood. The bitter orange tree gives three quite different oils, from the peel, the leaves (petitgrain) and the blossom (neroli), so the part used matters as much as the name.
An "x" between genus and species, as in Mentha x piperita, marks a hybrid. "Syn." means synonym, an older or alternative name for the same plant. Names also change as botanists learn more: rosemary was moved into the sage genus in 2017, so one bottle may say Rosmarinus officinalis and another Salvia rosmarinus, with the same oil inside.
When you buy, look for the botanical name, part used, country of origin, method (for citrus, pressed or distilled) and a batch number. "Fragrance oil", "aroma oil" and "nature identical" usually mean a synthetic perfume, and "therapeutic grade" is a marketing phrase with no agreed standard behind it.
What a chemotype is
Plants of one species can make oils with quite different chemistry depending on genes, climate, soil and harvest time. When one compound reliably dominates, the oil is sold as a chemotype, shortened to "ct." on the label. Rosemary comes as ct. cineole, ct. camphor and ct. verbenone. Thyme ct. linalool is far kinder to skin than thyme ct. thymol. Niaouli has a cineole type and a nerolidol type. Where the safety advice depends on the chemotype, the table says so.
Essential oils A to Z
| Oil | Botanical name | Part used | Main method | Scent | Common home uses | Cautions |
|---|---|---|---|---|---|---|
| Benzoin | Styrax benzoin (Sumatra), S. tonkinensis (Siam) | Resin tapped from the bark | Solvent extraction (resinoid) | Warm, vanilla-like, balsamic | Base note in winter blends | Often sold thinned with a solvent. Can sensitise skin: dilute low |
| Bergamot | Citrus bergamia | Fruit peel | Cold pressing | Bright citrus with a floral, tea-like edge | Diffuser blends, room sprays | Strongly phototoxic when pressed: 0.4% maximum on skin that will see sun. Bergapten-free (FCF) oil avoids this |
| Black pepper | Piper nigrum | Dried unripe fruit (peppercorns) | Steam distillation | Dry, warm, sharp spice | Warming massage blends after exercise | Use fresh; oxidised oil can irritate. Dilute low |
| Cajuput | Melaleuca cajuputi | Leaves and twigs | Steam distillation | Camphor-like, fresh, faintly fruity | Steam inhalation, winter diffusing | Rich in 1,8-cineole: not on or near the face of babies and young children |
| Cedarwood, Atlas | Cedrus atlantica | Wood | Steam distillation | Soft dry wood with a honeyed note | Base note, beard and hair blends | Low risk. "Virginian cedarwood" is a different oil from a juniper (Juniperus virginiana) |
| Chamomile, German | Matricaria chamomilla (syn. M. recutita) | Flowers | Steam distillation | Strong, hay-like, herbal, slightly bitter | Low-dilution skin blends | Daisy-family allergy (ragweed, chrysanthemum): patch test. Deep blue; stains fabric |
| Chamomile, Roman | Chamaemelum nobile (syn. Anthemis nobilis) | Flowers | Steam distillation | Sweet, apple-like, herbal | Evening bath and massage blends | Daisy-family allergy: patch test |
| Cinnamon bark | Cinnamomum verum (syn. C. zeylanicum) | Inner bark | Steam distillation | Hot, sweet spice | A drop in a winter diffuser blend | Strong skin sensitiser: keep off skin and out of baths. Cinnamon leaf and cassia are different oils, also irritant |
| Clary sage | Salvia sclarea | Flowering tops | Steam distillation | Musky, herbal, slightly nutty | Massage blends, evening diffusing | No major hazards known; often avoided in pregnancy as a precaution |
| Clove bud | Syzygium aromaticum | Dried flower buds | Steam distillation | Warm sweet spice, like a dental surgery | Seasonal diffuser blends | Strong skin irritant: 0.5% or less, or diffuse only. Not for young children or people on blood thinners |
| Cypress | Cupressus sempervirens | Needles and twigs | Steam distillation | Fresh, green, woody, a little smoky | Leg massage blends, foot baths | Use fresh; oxidised oil can irritate |
| Dill | Anethum graveolens | Seeds or whole herb | Steam distillation | Fresh, sweet, caraway-like | Occasional blending, rarely used alone | Generally mild. Indian dill seed oil (A. sowa) differs and is avoided in pregnancy |
| Eucalyptus (blue gum) | Eucalyptus globulus | Leaves | Steam distillation | Sharp, clearing, camphor-like | Steam inhalation, cleaning sprays | Rich in 1,8-cineole: not on or near the face of babies and young children. Poisonous if swallowed |
| Fennel, sweet | Foeniculum vulgare var. dulce | Crushed seeds | Steam distillation | Sweet aniseed, liquorice | Abdominal massage blends | Avoid in pregnancy, breastfeeding, epilepsy and hormone-sensitive conditions. Not for young children |
| Frankincense | Boswellia carterii, B. sacra (also B. serrata, B. frereana) | Gum resin | Steam distillation | Fresh, peppery lemon over incense | Face and body blends, quiet diffusing | Low risk when fresh; oxidised oil can irritate |
| Geranium | Pelargonium graveolens | Leaves and stems | Steam distillation | Rosy, green, slightly minty | Skin blends, floral diffuser blends | Can irritate very sensitive skin: patch test |
| Ginger | Zingiber officinale | Rhizome (root) | Steam distillation | Warm, earthy spice with a lemony lift | Warming massage blends, a travel tissue | Low risk; use fresh |
| Grapefruit | Citrus paradisi | Fruit peel | Cold pressing | Tangy, bittersweet, fresh | Morning diffuser blends, room sprays | Pressed oil is phototoxic: 4% maximum on sun-exposed skin. Oxidises quickly |
| Hinoki (Japanese cypress) | Chamaecyparis obtusa | Wood, sometimes leaves | Steam distillation | Clean lemony wood, like a cypress bathtub | Bath blends, diffusing | Low risk; use fresh |
| Jasmine | Jasminum grandiflorum (also J. sambac) | Flowers | Solvent extraction (absolute) | Rich, heady, warm floral | Perfume blends, one drop in a large blend | May hold solvent traces and can sensitise: use very low. Often adulterated |
| Juniper berry | Juniperus communis | Berries | Steam distillation | Fresh, peppery, gin-like | Massage blends, foot baths | Use fresh; oxidised oil can irritate. Berry and twig oils differ |
| Lavender | Lavandula angustifolia (syn. L. officinalis) | Flowering tops | Steam distillation | Soft floral, herbal, clean | Bedtime use, baths, all-purpose blends | Among the gentlest, but oxidised oil can sensitise. Not the same as lavandin or spike lavender |
| Lemon | Citrus limon | Fruit peel | Cold pressing (distilled also sold) | Sharp, clean, zesty | Cleaning sprays, morning diffusing | Pressed oil is phototoxic: 2% maximum on sun-exposed skin. Distilled lemon is not |
| Lemongrass | Cymbopogon citratus, C. flexuosus | Leaves | Steam distillation | Strong lemon and cut grass | Summer diffusing, cleaning sprays | Citral can sensitise: about 0.7% maximum on skin. Avoid on damaged skin and young children |
| Lime | Citrus aurantiifolia | Fruit peel, or whole fruit | Cold pressing or steam distillation | Sharp, sweet-sour, zesty | Diffuser and room-spray blends | Pressed oil is phototoxic: 0.7% maximum on sun-exposed skin. Distilled lime is not |
| Mandarin | Citrus reticulata | Fruit peel | Cold pressing | Sweet, soft, gentle citrus | Family-room diffusing, low-dose blends for older children | Low phototoxic risk. Oxidises like other citrus |
| Marjoram, sweet | Origanum majorana | Leaves and flowering tops | Steam distillation | Warm, herbal, gently spicy | Massage blends for tight shoulders, evening baths | Low risk. Spanish marjoram is a thyme (Thymus mastichina) |
| Myrrh | Commiphora myrrha | Gum resin | Steam distillation (resinoid also sold) | Smoky, bitter, warm, earthy | Balms for dry skin, incense-like blends | Best avoided in pregnancy and breastfeeding |
| Neroli | Citrus aurantium | Blossom of the bitter orange tree | Steam distillation | Honeyed floral with a bitter green edge | Face blends, perfume | Low risk and not phototoxic. Costly, so often diluted or faked |
| Niaouli | Melaleuca quinquenervia | Leaves and twigs | Steam distillation | Fresh, camphor-like, softer than eucalyptus | Winter inhalation, diffusing | Cineole type: not on or near the face of babies and young children |
| Orange, bitter | Citrus aurantium | Fruit peel | Cold pressing | Drier and more bitter than sweet orange | Perfume and room blends | Pressed oil is phototoxic: 1.25% maximum on sun-exposed skin |
| Orange, sweet | Citrus sinensis | Fruit peel | Cold pressing | Sweet, juicy, bright | Diffusing, cleaning sprays, first blends | Not considered phototoxic. Oxidises fast: use within about a year of opening |
| Palmarosa | Cymbopogon martinii | Leaves (grass) | Steam distillation | Soft rose with grass and lemon | Skin blends, rose-like diffuser blends | Mild; geraniol can sensitise a few people. Patch test |
| Patchouli | Pogostemon cablin | Dried leaves | Steam distillation | Deep, earthy, sweet, musty | Base note, perfume | Low risk. Strong: one drop goes a long way |
| Peppermint | Mentha x piperita | Leaves and flowering tops | Steam distillation | Cool, sharp mint | Tissue inhalation, cooling foot blends | Menthol: not on or near the face of babies and young children. Stings eyes and broken skin. Dilute low |
| Petitgrain | Citrus aurantium | Leaves and twigs of the bitter orange tree | Steam distillation | Green, woody, faintly floral | Evening diffusing, a cheaper partner for neroli | Low risk; not phototoxic |
| Rose | Rosa damascena (also R. x centifolia for absolute) | Petals | Steam distillation (otto) or solvent extraction (absolute) | Deep, sweet, honeyed rose | Face blends, perfume | Use at very low levels. Costly and widely adulterated. Otto turns solid when cool |
| Rosemary | Salvia rosmarinus (formerly Rosmarinus officinalis) | Leaves and flowering tops | Steam distillation | Fresh, herbal, camphor-like | Morning diffusing, scalp blends | Cineole and camphor: not on or near the face of young children. Camphor types best avoided in pregnancy and epilepsy |
| Sandalwood | Santalum album (Australian: S. spicatum) | Heartwood | Steam distillation | Soft, creamy, long-lasting wood | Perfume, face and body blends | Low skin risk. Wild Indian sandalwood is overharvested: ask about the source |
| Tea tree | Melaleuca alternifolia | Leaves and twigs | Steam distillation | Medicinal, fresh, slightly spicy | Diluted on blemish-prone skin, cleaning sprays | Oxidised oil is a common cause of skin allergy: keep capped and cool. Poisonous if swallowed |
| Vetiver | Vetiveria zizanioides (now Chrysopogon zizanioides) | Roots | Steam distillation | Smoky, earthy, deep | Base note, bedtime blends | Low risk. Very thick: warm the bottle in your hand |
| Ylang ylang | Cananga odorata | Flowers | Fractional steam distillation | Sweet, heady, creamy floral | Perfume, evening massage blends | Can sensitise above about 0.8%. Heavy scent can bring on headaches |
| Yuzu (Japanese citron) | Citrus junos | Fruit peel | Cold pressing or steam distillation | Tart and fresh, between grapefruit and mandarin | Winter diffusing, diluted bath blends | Less studied than other citrus: give pressed yuzu the same sun care as lemon |
Citrus oils and sunlight
Some pressed citrus oils contain furanocoumarins, compounds that react with ultraviolet light. Put one of these oils on your skin, go out in the sun or use a sunbed within the next 12 hours, and the result can be a burn, blisters, or brown marks that last for months. Diffusing the oil and using it in rinse-off products such as shower gel do not carry this risk.
The limits below are the maximum levels for leave-on products on sun-exposed skin suggested by Robert Tisserand and Rodney Young in their book Essential Oil Safety. If you combine two of these oils, the risks add up, so use each at no more than half its limit.
| Oil | Cold-pressed oil | Safer choice for skin |
|---|---|---|
| Bergamot | Phototoxic, 0.4% maximum | Bergapten-free oil, labelled FCF |
| Lime | Phototoxic, 0.7% maximum | Distilled lime |
| Bitter orange | Phototoxic, 1.25% maximum | Diffuse it, or use on covered skin |
| Lemon | Phototoxic, 2% maximum | Distilled lemon |
| Grapefruit | Phototoxic, 4% maximum | Diffuse it, or stay under the limit |
| Sweet orange, mandarin | Not considered phototoxic | Normal dilution rules apply |
| Yuzu | Less studied | Treat it as you would lemon |
Angelica root and cumin oils are phototoxic too, though neither is common in home kits.
Ten oils in more detail
Lavender
True lavender, Lavandula angustifolia, is where most people start: most noses like it, it blends with almost anything, and it is low risk on skin when fresh and diluted. Lavandin (L. x intermedia) is a cheaper hybrid with a sharper camphor edge, and spike lavender (L. latifolia) carries more camphor still. Lavandula stoechas is high in camphor and fenchone and is best avoided in pregnancy and by people with epilepsy. Small studies suggest inhaled lavender may help some people feel calmer, but the trials are small and hard to blind, since everyone knows what lavender smells like.
Tea tree
Tea tree kills many bacteria and fungi in laboratory tests, and small trials of 5% tea tree gels for mild acne have found a modest benefit. Its biggest home risk is age: oxidised tea tree oil is a well-known cause of allergic rashes, so buy small bottles, keep the cap tight, and throw out oil that smells harsh or turpentine-like. Swallowed tea tree oil has made children drowsy and unsteady, and it is toxic to cats and dogs; our piece on essential oils around children and pets has more.
Sweet orange
Cheap, cheerful and pressed from peel left over by the juice industry, sweet orange makes a good first oil. Unlike bergamot and lime it is not considered phototoxic. It is mostly limonene, which oxidises quickly once the bottle is open, and oxidised limonene can sensitise skin. Write the opening date on the label and use it within about a year. A few small studies, some in dental waiting rooms, have looked at orange scent and anxiety, with modest and mixed results.
Peppermint
Peppermint, a hybrid of watermint and spearmint, owes its cool feel to menthol. Enteric-coated peppermint oil capsules are sold as a medicine for irritable bowel syndrome in some countries, but that is a measured product made to be swallowed; an aromatherapy bottle is not, so never take it by mouth. Japanese hakka (corn mint, Mentha arvensis), long grown in Hokkaido, is even richer in menthol and needs the same care. Menthol near a baby's face can trigger breathing problems, and safety reviewers advise people with G6PD deficiency or some heart rhythm problems to ask a doctor first.
Eucalyptus
"Eucalyptus" on a label usually means blue gum, Eucalyptus globulus. Eucalyptus radiata smells softer. Lemon eucalyptus (Corymbia citriodora) is a different oil again, and not the same as the registered insect repellents sold as "oil of lemon eucalyptus", which the US CDC says should not be used on children under 3. For steam inhalation, 1 to 2 drops in a bowl of hot water is plenty; keep eyes closed. The NHS advises against steam inhalation for children because of the scalding risk. Swallowed eucalyptus oil is a known cause of serious poisoning in young children.
Frankincense
Boswellia carterii and B. sacra are so close that many botanists treat them as one species. Boswellic acids, studied in tablet extracts for joint pain, are too heavy to distil, so that research does not apply to the oil. Online claims that frankincense oil treats cancer are not supported by evidence. Wild trees are being overtapped in parts of the Horn of Africa, so ask about sourcing.
Geranium
Geranium oil comes from Pelargonium, not from the hardy cranesbill Geranium of garden borders. It pairs well with citrus and lavender and is often used to stretch expensive rose. Most people tolerate it well, though a patch test is sensible on sensitive skin.
Roman chamomile
The name chamomile comes from Greek words for "earth apple", and Roman chamomile does smell of apples. German chamomile is a different plant: it turns deep blue during distillation as a compound called chamazulene forms. Both belong to the daisy family, so anyone with a ragweed or chrysanthemum allergy should patch test. Roman chamomile is often chosen for gentle evening blends at 1% or less.
Ylang ylang
The flowers are distilled in stages, giving fractions: "extra" comes first and smells most floral, followed by grades I, II and III, while "complete" is the whole run. It can sensitise skin above about 0.8%, and one drop in a blend is usually enough.
Rosemary
With rosemary, check the chemotype: ct. cineole (often from Morocco or Tunisia) is clearing and sharp, ct. camphor (often Spanish) is harsher, and ct. verbenone is softer. Its popularity in scalp blends rests on very little research, so treat claims about hair regrowth with caution.
Oils best left out of home use
Some oils that turn up in older books and online shops are not worth the risk at home. Pennyroyal (Mentha pulegium) has caused liver failure and deaths when swallowed. Wintergreen (Gaultheria procumbens) and sweet birch (Betula lenta) are almost pure methyl salicylate, a relative of aspirin; small amounts swallowed have killed children, and they are unsuitable for anyone taking blood thinners or allergic to aspirin. Common sage (Salvia officinalis), tansy, thuja and wormwood contain thujone, and hyssop contains pinocamphone; both compounds can trigger seizures. Sassafras is rich in safrole, which has caused cancer in animal studies.
Carrier oils
A carrier oil is a plain, fresh plant oil used to dilute essential oils before they touch skin. Common choices:
- Sweet almond (Prunus amygdalus var. dulcis): light and all-purpose. Skip it if you have a nut allergy.
- Jojoba (Simmondsia chinensis): really a liquid wax, so it keeps well; good on the face.
- Rice bran (Oryza sativa): light, and sold in most Japanese supermarkets as rice oil.
- Camellia (Camellia japonica): tsubaki oil, the traditional Japanese oil for hair and skin.
- Grapeseed (Vitis vinifera): very light but goes rancid quickly.
- Sunflower (Helianthus annuus): cheap and mild; high-oleic versions last longer.
- Avocado (Persea americana): rich and slow to absorb, usually 10 to 20% of a blend. See our guide to avocado carrier oil.
Before you open a new bottle
- Check the cautions column against everyone who will smell or touch the oil: pregnancy, breastfeeding, babies and children, epilepsy, asthma, pets.
- Dilute for skin, and patch test a new blend on the inner forearm, checking after 24 to 48 hours.
- Keep bottles capped, cool, dark and out of children's reach, with the dropper insert in place.
- If oil gets in an eye, rinse with plenty of clean running water for at least 10 minutes, and get medical advice if pain or blurred vision continues.
- If anyone swallows an essential oil, especially a child, do not make them vomit. Contact a doctor or a poison information service straight away, and call 119 in Japan (or your local emergency number) for drowsiness, choking, coughing fits, trouble breathing or a seizure.
- See a doctor about a rash that spreads, blisters or will not settle, and if you are pregnant, take regular medicines (blood thinners in particular) or have asthma or epilepsy, ask your doctor or pharmacist before using oils on your skin.