Fig Leaf (Ficus carica)

This is my personal "Don't even think about it!" list. These oils are really dangerous to handle or have around the house at all. Many are banned from use in cosmetics or as flavorings. Some can be fatal if accidentally swallowed, and others can cause immediate skin sensitization. These oils are are are produced because they have industrial uses, but they have little to no medicinal, aromatherapy, flavoring, or other household value.

These are only the dangerous oils that I know about. Just because an oil is listed here doesn't mean it's safe. Also check out my irritants & sensitizers page for oils unsafe to use on the skin.

Please do not copy, but rather link to this page since I will be updating it as new oils and knowledge become available.

Methyleugenol: It has become clear that methyleugenol (ME), a phenolic compound with a clovelike aroma, is a systemic carcinogen (13-18) in rodents and damages DNA in human cell cultures. ME has a threshold effect - that is to say small amounts are safe but large amounts carcinogenic. Most of us are already exposed to small (and probably safe) amounts of methyleugenol through common flavorings, so the IFRA has published some very restrictive recommendations about the use of ME in fragrances, including in room fragrancing. New safe usage guidelines for most of these oils fall below 0.1% for general skin use and below 2% for inhalation (like in aromalamps). It's not clear whether ME actually makes it through the skin in aromatherapy use, but these oils often contain over 5% ME and should probably be avoided.

Allspice (Pimenta dioica, P. officinalis)
Basil, linalool chemotype (Oncimum basilicum ct. linalool)
Bay, West Indian (Pimenta racemosa) 0-5%
Laurel Leaf or Bay Laurel (Laurus nobilis)
Melaleuca bracteata - very high amounts!
Ravensara (Ravensara aromatica)
Tarragon (Artemesia dracunculis)
Tea Tree, methyl eugenol chemotype (Melaleuca leucadendra)

These oils contain only small amounts of ME and are of concern if you are following the new IFRA guidelines.

Armoise (Artemesia vulgaris) <1%
Basil, methyl chavicol (Oncimum basilicum), none to 1%
Carrot (Daucus carota), very rarely present, <1%
Cassia (Cinnamomum cassia), rarely present <0.5%
Citronella (Cymbopogon nardus), none to 1%
Cardamom (Elettaria cardamomum), <0.5%
Elemi (Canarium luzonicum) - tiny amounts
Hyssop (Hyssopus officinalis) <0.5%
Myrtle (Myrtus communis) - up to 2.5%
Nutmeg (Myristica fragrans) <1%
Mace (Myristica fragrans) <0.2%
Wild Oregano (Coleus aromaticus) - 2%
Rose (Rosa spp, all), none to 5%
Rosemary (Rosemarinus officinalis), tiny amounts
Savory, Winter (Satureja montana) rarely present, <1%
Ylang ylang (Canaga odorata var. genuina) - rarely present, <0.2%

Birch and Wintergreen: I debated about listing sweet birch and wintergreen as toxic because they are medicinal and widely used as flavorings. Both oils are mostly methyl salicylate, a common analgesic found in many over-the-counter medications. They're on my blacklist becuse a typical 15 ml bottle contains more than enough methyl salicylate to kill a person if ingested or spilled on the skin (6,9). They are also dangerous to use in combination with many common over-the-counter medicines including aspirin, Pepto Bismol, and arthritis medicines and creams. These oils are particularly dangerous to children since they smell sweet and minty.

Thujone: There is an ongoing debate about thujone in the aromatherapy community. Alpha-thujone of absinthe fame is clearly orally toxic, causing seizures and brain damage in low, chronic doses and death in high doses. ß-thujone is less toxic, but still dangerous orally. However, it is unclear whether thujone is absorbed by the skin or by inhalation, and many people have used thujone-containing oils externally with no ill-effects. Unfortunately, there are really no good studies showing lack of absorption, or long-term safety of external thujone use. Because brain damage is permanent, I believe that the risks of using oils containing high amounts of thujone currently outweigh the benefits.

Orally toxic oils - You might not want these oils around either, although they smell pretty good and some are approved as flavorings in small amounts. Drinking a bottle of any of these oils could kill a small child. Note that many other essential oils are toxic if consumed in large quantities, so please keep all bottles in a safe place away from children and pets.

Arnica infusion (Arnica montana) - oral toxin, unsafe on broken skin
Basil (Ocimum spp.) - therapeutic, but orally toxic
Camphor, White (Cinnamomum camphora)
Clove Bud, Leaf, and Stem (Eugenia spp.)
Cornmint (Mentha arvensis)
Eucalyptus globulus - Great for inhalation, but very orally toxic
Hyssop (Hyssopus officinalis) - pinocamphone; cumulative toxin
Mugwort, Armoise (Artemisia vulgaris) - neurotoxic thujone
Nutmeg (Myristica fragrans) - neurotoxic myristicin, carcinogenic safrole
Oregano (Oreganum spp.)
Pennyroyal (Mentha pulegium) - oral hepatotoxin d-pulegone
Sage, Dalmatian (Salvia officinalis) - 18%-55% neurotoxic alpha-thujone (11)
Sage (S. fruticosa, S. lavendulaefolia) - neurotoxic alpha-thujone
Sagebrush (S. trilobia) - neurotoxic alpha-thujone
Thymus (Thymus zygus)
Tarragon (Artemesia dracunculis) - toxic estragole, neurotoxic alpha-thujone
Yarrow (Achillea millefolium) - Up to 10% alpha-thujone (10)

References