It is vitally important to educate yourself about essential oils before using them. Some essential oils should never be used while others have harmful properties depending upon certain circumstances.

An additional, professional resource regarding hazardous essential oils is Essential Oil Safety: A Guide for Health Care Professionals by Robert Tisserand, Tony Balazs.

Please note that any information given or shared on this page is for educational purposes only. Paula Vaughan is not responsible for any injuries associated with essential oil use or misuse.

~ Oils that should NEVER be used in aromatherapy Almond, bitter, Prunus amygdalis, var. amara Aniseed, Pimpinella anisum Arnica, arnica montana Boldo Leaf, peumus boldus Calamus, acorus calamus-acorus Camphor, cinnamomum camphorus Cassia, cinnamomum cassia Cinnamon Bark, cinnamomum zeylanicum Costus, saussurea lappa Elecampane, inula helenium Fennel (bitter), foeniculum vulgare Horseradish, cochlearia armorica Jaborandi Leaf, pilocarpus jaborandi Mugwort (Armoise), artemisia vulgaris Mustard, brassica nigra Origanum, origanum vulgare and Origanum Spanish, thymus capitatus Pennyroyal N.American, hedeoma puleagilides and Pennyroyal European, mentha pulegium Dwarf Pine, pinus pumilio Rue, ruta graveolens Sage, ruta graveolens (this is different than Clary Sage) Sassafras, sassafras albidum and Sassafras Brazilian, Ocotea cymbarum Savin, juniperus sabina Savory Summer satureia hortensis and Savory Winter, satureia montana Southernwood, artemisia abrotanum Tansy, tanacetum vulgare Thuja (Cedarleaf), thuja occidentalis Thuja Plicata, thusa plicata Wintergreen, gaultheria prodcumbens Wormseed, chenopodium anthelminiticum Wormwood, artemisia absinthium ~ Oils that should not be used by epileptics Fennel (sweet) Hyssop Rosemary Sage (should not use at all ever) Wormwood (should not use at all ever) ~ Oils that should not be used during pregnancy It is probably a good idea not to use essential oils at all during pregnancy to avoid any risk. Basil Birch Cedarwood Chamomile *** Clary Sage Cypress Geranium *** Hyssop Jasmine Juniper Lavender *** Marjoram Myrrh Nutmeg Peppermint Rose *** Rosemary Tarragon Thyme *** These oils (chamomile, geranium, lavender and rose) may be used in small amounts and very diluted after the first trimester if there is NO history of miscarriage. ~ Oils with a risk of toxicity Do not use these oils for more than a few days at a time. Basil Cedarwood Cinnamon leaf Eucalyptus Fennel (sweet) Hyssop Lemon Orange Nutmeg Thyme ~ Oils that can be skin irritants Dilute these oils 1% (1 drop only) before use. Angelica Black Pepper Cinnamon Leaf Citronella Clove (all parts) Ginger Lemon Lemongrass Lemon Verbena Orange Nutmeg Peppermint ~ Oils that should not be used before going into the sun Angelica Bergamot Lemon Orange