Essential oil safety: cautions, contra-indications & dilutions

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-IJ - RS - Z
Almond, bitterJaborandi leafSage (Dalmation)*
Armoise (Mugwort)LanyanaSassafras
Basil with high estragole
Mugwort (Armoise)Sassafras (Brazilian)
Birch*MustardSavin
Boldo leaf
OriganumSavory (Summer)
Cade (unrectified)
Origanum (Spanish)Savory (Winter)
CalamusPennyroyal (European)Snakeroot
Camphor (brown and yellow)Pennyroyal (North American)Southernwood
CassiaPine (dwarf)Tansy
Cinnamon barkRueTarragon
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 oilCautions / Contra-indications
Sweet AlmondAvoid with nut allergies.
AngelicaPhoto-sensitivity - avoid exposure to direct sunlight and sunbeds after application.
ArnicaOnly use on unbroken skin.
BasilDo 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.
BergamotPhoto-sensitivity - avoid exposure to direct sunlight and sunbeds after application.
Black PepperMay over stimulate the kidneys
CajuputMay irritate the skin.
Cedarwood AtlasDo not use during pregnancy.
Roman ChamomileDo not use if allergic to Roman Chamomile and other compositaes.
Cinnamon LeafSevere dermal irritant and sensitiser - use with care. Do not use Cinnamon bark.
Clary SageDo not use during pregnancy. Do not use if alcohol has been consumed. Avoid in cases of hormone related cancers.
Clove BudPotential skin irritant and sensitising agent.
Eucalyptus Do not use during pregnancy. Do not use on babies and children under the age of 3.
FennelDo not use during pregnancy. Avoid with epilepsy.
GeraniumCases of dermatitis have been reported in hypersensitive individuals.
GingerMay cause sensitisation in some individuals.
HazelnutHazelnuts may cause immunological contact urticaria and possibly anaphylaxis.
St John's Wort (Hypericum)Photo-sensitivity - avoid exposure to direct sunlight and sunbeds after application.
HyssopDo not use during pregnancy. Avoid with epilepsy.
JuniperberryDo not use during pregnancy. Do not use if kidneys are inflamed.
LemonPhoto-sensitivity - avoid exposure to direct sunlight and sunbeds after application. May cause sensitisation in some individuals.
LemongrassIrritating and sensitising in some individuals.
LimeThe expressed oil is phototoxic - avoid exposure to direct sunlight and sunbeds after application. 
Sweet MarjoramDo not use during pregnancy.
MelissaPossible skin irritant. Best avoided in pregnancy.
MyrrhDo not use during pregnancy.
NutmegDo not use during pregnancy. Use with care as the myristicin can cause hallucinations.
OliveDandruff is made worse if olive oil is applied to a dry scalp. The oil may cause an allergic reaction.
PeppermintMay occasionally be sensitising. Do not use during pregnancy or while breastfeeding. Do not use on children under the age of 3.
PinePotential dermal irritant in some individuals (especially dwarf pine)
RosemaryDo not use during pregnancy, or if suffering with epilepsy or high blood pressure.
SpearmintDo not use during pregnancy. Avoid with young children.
TagetesPossible skin irritant.
Tea TreePossibly sensitising to some individuals.
ThymePossibly sensitising to some individuals.
WheatgermAvoid with wheat flour allergies
Ylang YlangExcessive 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 rangeRecommended dilution
Babies 0-12 months1 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.
Adults2 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.

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