Irritants & Sensitizers  

Styrax (Liquidambar orientalis)




Pine (Pinus spp.)

The following oils and absolutes are dangerous strong sensitizers. Given enough exposure, many people will become severely allergic to these oils and cross-sensitized to others. They're best left to the aroma lamp or avoided altogether. Now that new IFRA methyleugenol (ME)recommendations have been released, I've marked the unsafe ME containing oils with a strikethrough. If you don't see an oil you are looking for on this page, be sure and check the Dangerous Oils page for a listing before you assume it's safe!

Irritant and strongly sensitizing
Cade (Juniperus oxycedrus) - crude extract
Cassia (Cinnamomum cassia) - also contains a trace of ME
Cinnamon Bark (Cinnamomum zeylanicum) - really a flavoring
Fir (Abies spp.) - if old; see below
Perilla (Perilla frutescens)
Pine Needle (Pinus spp.) - if old; see below
Spruce (Picea spp.) - if old; see below
Tea Tree (Melaleuca alternifolia) - if old; see below

Strongly sensitizing
Benzoin (Styrax benzoin)
Citrus (Citrus spp.) if old; see below
Copaiba Balsam (Copaifera officianalis) - if old and oxidized
Oak Moss absolute (Evernia prunastri)
Opoponax (Commiphora erythraea)
Styrax, Styrax Benzoin (Liquidambar orientalis)
Tolu Balsam (Myroxylon balsamuim var. balsamium)
Tree Moss or Cedar Moss absolute (Evernia furfuracea, Usnea barbata)

Oils that are steam distilled from styrax resin (Liquidambar orientalis) are less sensitizing and are permitted by the IFRA at very low concentrations. However, I have found steam distillates to be rare and would request to see the GC of anything I might buy for skin use.

Old evergreen needle (Pinaceae family - confiers), tea tree, or expressed citrus rind oils can become quite strong sensitizers because of the gradual buildup of reactive epoxides and peroxides in the oil. Affected oils are Abies, Picea, Pinus, and Tsuga spp., tea tree, and all expressed citrus peel oils, inluding bergamot, orange, lemon, lime, grapefruit, clementine, mandarin, and tangerine. Personally, I'm planning on replacing these oils every 6 months on Martin Watt's recommendation. (5,7) Storing evergreen oils in the dark and citrus oils in the refrigerator helps keep them safe for skin use. You can also add Vitamin E T-50 at a rate of 0.05% to help preserve the oils, or top them off with a nitrogen/argon wine preservation gas.

Strong or moderate irritants - Oils which sensitize as well as irritate are marked as sensitizers. Many aromatherapists don't use this group of oils on the skin unless there is a compelling therapeutic reason. Some contain eugenol which can be a sensitizing agent. Oils marked STRONG should never be used on skin.

Allspice (Pimenta dioica, P. officinalis) Contains ME
Aniseed (Pimpinella anisum)
Basil, Holy (Ocimum sanctum, O. gratissimum)
Bitter Almond FFPA (Prunus dulcis var amara) - can cause dermatitis
Camphor, White or rectified (Cinnamomum camphora)
Cinnamon Leaf (Cinnamom zeylanicum) - sensitizer; don't confuse with bark!
Citronella (Cymbopogon nardus)
Clove (Syzgium aromaticum)
Dwarf Pine Needle (Pinus mungo var. pumilio) STRONG
Fennel, Bitter (Foeniculum vulgare var. vulgare) - sensitizer
Garlic (Allium sativum)
Ginger CO2 (Zingiber officinale) - sensitizer, burns if too concentrated
Laurel Leaf or Bay Laurel (Laurus nobilis) Contains ME
Lemon Scented Myrtle (Backhousia citriodora)
Melissa (Melissa officinalis) - IFRA prohibited until further study
Onion (Allium cepa)
Orange, Sweet (Citrus sinensis)
Oregano (Origanum vulgare)
Parsley Leaf (Pertoselinum sativum)
Pepper, Black or White (Piper nigrum)
Savory, Summer Savory (Satureja hortensis)
Savory, Winter (Satureja montana) STRONG, contains ME
Spanish Oregano (Thymus capitatus) STRONG
Thyme (Thymus vulgaris) - Some chemotypes very irritating and sensitizing
Turmeric (Curcuma longa)

Milder sensitizers and irritants - Aromatherapists do use these oils on skin, but they are careful about how often and how much oil. It's best to dilute these oils well and test the dilution on a small area of skin before using them for a bath or massage. Avoid overuse of sensitizing oils.

Anise, Star (Illicium verum)- sensitizer
Basil (Oncimum basilicum)
Cajeput (Melaleuca leucadendron)
Citrus spp.
Cardamom (Elettaria cardamomum) - can contain ME
Cornmint (Mentha arvensis)
Eucalyptus globulus - rubefacient
Fir (Abies spp.)
Ginger (Zingiber officinale) - sensitizer
Hyssop (Hyssopus officinalis) - skin use is controversial due to oral toxicity
Juniper Berry (Juniperus communis) - rubefacient
Lemon (Citrus limonum) - sensitizer
Lemongrass (Cymbopogon citratus, C. flexuosus) - rubefacient
Litsea or May Chang (Litsea cubeba) - sensitizer
Marjoram, Wild (Thymus mastichina)
Mimosa (Acacia dealbata)
Pennyroyal (Mentha pulegium) - use is controversial due to oral toxicity (not irritant)
Petitgrain (Citrus aurantium) - occasional sensitizer
Peppermint (Mentha piperita)
Pine Needle (Pinus spp.)
Spearmint (Mentha spicata)
Spruce (Picea spp.)
Tea Tree (Melaleuca alternifolia) - can sensitize if used undiluted
Valerian (Valeriana officinalis)

Allergens and occasional sensitizers - These safer oils can cause dermatitis, sensitization or allergic reactions in atopic people. People with cosmetic allergies may react as well. Remember to test the diluted oil on a small area first, before using it all over your body.

Arnica infusion (Arnica montana) - reactions are common
Cananga (Cananga odorata var. macrophyla)
Caraway (Carum carvi)
Cassie absolute (Acacia farnesiana)
Celery Seed (Apium graveolens) - rare
Cistus absolute (Cistus ladaniferus)
Clary Sage (Salvia sclarea)
Coriander (Coriandrum sativum)
Eucalyptus spp. - rare
Fennel, Sweet (Foeniculum vulgare var. dulce)
Geranium, Rose (Pelargonium graveolens, P. roseum)
Hops (Humulus lupulus)
Jasmine (Jasminum spp.)
Lavandin (Lavandula angustifolia x latifolia)
Lavender (Lavandula angustifolia)
Myrrh absolute (Commiphora spp.)
Neroli (Citrus aurantium var. amara)
Hyacinth absolute (Hyacinthus orientalis)
Palmarosa (Cymbopogon martinii)
Rose (Rosa spp.) - non-irritant, can sensitize
Sandalwood (Santalum album)
Tuberose concrete, absolute (Polyanthes tuberosa)
Vanilla resinoid (Vanilla planifolia)
Violet Leaf absolute (Viola odorata)
Ylang ylang (Canaga odorata var. genuina)

Phototoxic - do not use on skin exposed to the sun. Oils marked slight may be used in dilution, according to the IFRA. It can take as long as 24 hours for photosensitizing effects to wear off.

Ammi visnaga
Angelica Root (Angelica archangelica)
Bergamot, expressed (Citrus bergamia) - only FCF is safe for skin
Bitter Orange, expressed (Citrus aruantium var. amara)
Cumin (Cuminum cyminum)
Dill Seed and Weed (Anethum graveolens)
Grapefruit, expressed (Citrus paradisi) - slight; IFRA limited to 4%
Lemon, expressed (Citrus limonum)
Lime, expressed (Citrus aurantifolia)
Mandarin, expressed (Citrus reticulata) - slight
Parsley Leaf (Pertoselinum sativum) - slight
Petitgrain Mandarin (Citrus reticulata)
Tagetes oil and absolute (Tagetes minuta, T. glanduifera, T. patula) STRONG
Tangerine, expressed (Citrus reticulata) - slight

Not adequately tested - These oils have not undergone formal, controlled testing. It is impossible to say how frequently people react or fail to react to them.

Amyris (Amyris balsamifera) - reports of contact sensitivity
Buchu (Agothosma betulina)
Catnip (Nepeta cataria)
Chamomile Maroc (Omensis multicaulis)
Damiana (Turnera diffusa)
Eucalyptus other than globulus or citriodora
Kanuka (Leptospermum ericoides)
Linden Blossom absolute (Tilia europa)
Manuka (Leptospermum scoparium)
Niaouli (Melaleuca quinquenervia, M. viridiflora)
Ravensara (R. anisata, R. aromatica)
Rosalina (Melaleuca ericifolia)
Spikenard (Nardostachys jatamansi) - historic use in India
Vitex or Chasteberry (Vitex agnus castus) - strong hormonal effects
Yarrow (Achillea millefolium) - the herb is a photosensitizer
Zdravetz (Geranium macrorrhizum)


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