While many essential oils and carrier oils can be used safely to promote good health and wellbeing, some should not be used at all in Aromatherapy and others should not be used in some circumstances. A comprehensive list of cautions and contra-indications are shown below in respect to the more popular essential oils and carrier oils used in Aromatherapy. It is recommended that only qualified aromatherapists use Cinnamon Leaf (Cinnamomum zeylanicum), Hyssop (Hyssopus officinalis) and Sage (Salvia officinalis).
Tisserand & Balacs (1995) and Davis (1988) suggest that the essential oils shown in the table below should not be used in Aromatherapy as they are potentially hazardous.
Essential oils that present risks of toxicity or skin irritation
| A-I | J – R | S – Z |
| Almond, bitter | Jaborandi leaf | Sage (Dalmation)* |
| Armoise (Mugwort) | Lanyana | Sassafras |
| Basil with high estragole | Mugwort (Armoise) | Sassafras (Brazilian) |
| Birch* | Mustard | Savin |
| Boldo leaf | Origanum | Savory (Summer) |
| Cade (unrectified) | Origanum (Spanish) | Savory (Winter) |
| Calamus | Pennyroyal (European) | Snakeroot |
| Camphor (brown and yellow) | Pennyroyal (North American) | Southernwood |
| Cassia | Pine (dwarf) | Tansy |
| Cinnamon bark | Rue | Tarragon |
| Clove leaf | Tea | |
| Costus | Thuja | |
| Elecampane | Verbena | |
| Fennel, bitter | Wintergreen* | |
| Fig leaf | Wormseed | |
| Horseradish |
Wormwood |
*Should only be used in moderation by qualified practitioners who know how to use them safely and responsibly.
Cautions and contra-indications
In some circumstances an individual may have a contra-indication in which certain essential oils and/or carrier oils should be avoided. This is because using the essential oil or carrier oil may increase a symptom or problem that may already exist or create other problems. Examples of contra-indications include high blood pressure, diabetes, open wounds etc. Some essential oils and carrier oils may be used but with caution, for example, oils that are known skin irritants. Table 2 provides a list of common essential oils and carrier oils together with associated cautions and contra-indications.
| Essential oil / carrier oil | Cautions / Contra-indications |
| Sweet Almond | Avoid with nut allergies. |
| Angelica | Photo-sensitivity – avoid exposure to direct sunlight and sunbeds after application. |
| Arnica | Only use on unbroken skin. |
| Basil | Do not use during pregnancy. Only Basil with methyl chavicol of 5% or less should be used in aromatherapy. Avoid using Basil with high content of methyl cinnamate. |
| Bergamot | Photo-sensitivity – avoid exposure to direct sunlight and sunbeds after application. |
| Black Pepper | May over stimulate the kidneys |
| Cajuput | May irritate the skin. |
| Cedarwood Atlas | Do not use during pregnancy. |
| Roman Chamomile | Do not use if allergic to Roman Chamomile and other compositaes. |
| Cinnamon Leaf | Severe dermal irritant and sensitiser – use with care. Do not use Cinnamon bark. |
| Clary Sage | Do not use during pregnancy. Do not use if alcohol has been consumed. Avoid in cases of hormone related cancers. |
| Clove Bud | Potential skin irritant and sensitising agent. |
| Eucalyptus | Do not use during pregnancy. Do not use on babies and children under the age of 3. |
| Fennel | Do not use during pregnancy. Avoid with epilepsy. |
| Geranium | Cases of dermatitis have been reported in hypersensitive individuals. |
| Ginger | May cause sensitisation in some individuals. |
| Hazelnut | Hazelnuts may cause immunological contact urticaria and possibly anaphylaxis. |
| St John”s Wort (Hypericum) | Photo-sensitivity – avoid exposure to direct sunlight and sunbeds after application. |
| Hyssop | Do not use during pregnancy. Avoid with epilepsy. |
| Juniperberry | Do not use during pregnancy. Do not use if kidneys are inflamed. |
| Lemon | Photo-sensitivity – avoid exposure to direct sunlight and sunbeds after application. May cause sensitisation in some individuals. |
| Lemongrass | Irritating and sensitising in some individuals. |
| Lime | The expressed oil is phototoxic – avoid exposure to direct sunlight and sunbeds after application. |
| Sweet Marjoram | Do not use during pregnancy. |
| Melissa | Possible skin irritant. Best avoided in pregnancy. |
| Myrrh | Do not use during pregnancy. |
| Nutmeg | Do not use during pregnancy. Use with care as the myristicin can cause hallucinations. |
| Olive | Dandruff is made worse if olive oil is applied to a dry scalp. The oil may cause an allergic reaction. |
| Peppermint | May occasionally be sensitising. Do not use during pregnancy or while breastfeeding. Do not use on children under the age of 3. |
| Pine | Potential dermal irritant in some individuals (especially dwarf pine) |
| Rosemary | Do not use during pregnancy, or if suffering with epilepsy or high blood pressure. |
| Spearmint | Do not use during pregnancy. Avoid with young children. |
| Tagetes | Possible skin irritant. |
| Tea Tree | Possibly sensitising to some individuals. |
| Thyme | Possibly sensitising to some individuals. |
| Wheatgerm | Avoid with wheat flour allergies |
| Ylang Ylang | Excessive use may cause nausea or headaches. |
Safe dilution rates
In order to use essential oils safely and effectively, it is important to ensure they are diluted in a suitable carrier, for example, carrier oils, base creams or lotions. This helps to minimise any adverse skin reactions and systemic toxicity. Essential oils should never be used neat on the skin or taken internally.
The chart below provides basic guidelines on safe dilution rates for use at home.
| Age range | Recommended dilution |
| Babies 0-12 months | 1 drop of essential oil in 15ml of carrier. Only use Lavender or Roman Chamomile. |
| Infants 1-6 years* | 1-2 drops of essential oil in 15ml of carrier. |
| Children 7-12 years* | 1 drop of essential oil in 4ml of carrier. |
| Children 12+ years* | 2 drops of essential oil in 4ml of carrier. |
| Adults | 2 drops of essential oil in 4ml of carrier. |
| During pregnancy or with the elderly, frail or infirm |
1 drop of essential oil in 4ml of carrier. |
* Click here to learn which essential oils are safe to use with babies and children.
Christine Fisk
Consultant Aromatherapist
Disclaimer & Safety Advice
Read other articles by Christine Fisk
References
Davis, P. (1988). Aromatherapy A-Z. Great Britain: C W Daniel Company Limited.
Tisserand, R., & Balacs, T. (1995). Essential Oil Safety, A Guide For Health Care Professionals. New York: Churchill Livingstone.