Most essential oils can be used, even if there are strong safety concerns, as long are they are diluted properly (see: Essential Oils and Cancer – potentially carcinogenic, and anti-carcinogenic essential oils). But there are some essential oils that are simply best avoided due to their toxicity.
According to Essential Oil Safety, the following essential oils “should not be used, either internally or externally.”
- Almond (Bitter, unrectified) Prunus dulcis, Prunus communis, Prunus amygdalus, Amydalus communis, Amygdalus dulcis
- Boldo Peumus boldus, Boldoa fragrans
- Cade (unrectified) Juniperus exycedrus
- Camphor (Brown)* Cinnamomum camphora, Laurus camphora
- Fig Leaf Ficus carica
- Horseradish Armoracia rusticana, Chochlearia armoracia, Armoracia lapathifolia
- Mustard Brassica nigra, Brassica juncea
- Pine (Huon) Dacrydium franklinii, Lagarostrobos franklinii
- Sassafras Sassafras albidum, Nectandra sanguinea, Ocotea odorifera, Ocotea pretiosa, Cinnamomum porrectum, Cinnamomum rigidissimum
- Savin Juniperus sabina
- Snakeroot Asarum canadense
- Tea Tree (Black)** Melaleuca bracteata
- Wormseed Chenopodium ambrosioides
*Tea Tree (Black) “Melaleuca bracteata” is not the same as the commonly used Tea Tree “Melaleuca alternifolia” which is safely used. If you are unsure which you have, check the Latin name.
**Camphor (Brown), Camphor (White), and Camphor (Yellow) all have the same Latin name of “Cinnamomum camphora.” So how do you tell the difference? If you have a GC/MS report available, check the constituents. Camphor (Brown) contains up to 60% safrole; Camphor (White) contains 40% or more limonene; Camphor (Yellow) contains 20% safrole.
Lea Harris is a Certified Clinical Aromatherapist Scholar's Program graduate from Aromahead Institute. This website, and its sister website, LearningAboutEOs, is home to educational advice and information about using essential oils safely. Lea founded and runs the Using Essential Oils Safely facebook group, with hundreds of new members joining each week. Lea is the author of The TRUTH About Essential Oil Safety, and the creator of Safe Essential Oil Labels and the UEOS App. You can find FREE classes here: Free Essential Oil Classes.
Lea received her herbalist certification through The Herbal Academy of New England. Lea is a contributing writer for Natural Herbal Living magazine, and blogs about herbs and natural living on her website, Nourishing Treasures.
Lea is Professional level member of the Alliance of International Aromatherapists.
Businesses, groups, and individuals can hire Lea to consult on safety, product formulation, and more on her website Lea Harris CCA.