Essential Oils, A users' guide

Oil Type	Safety Data	Monoterpene content	Other terpene content
Black Pepper	Black pepper oil may cause irritation to sensitive skins and using too much could over-stimulate the kidneys and should be avoided in pregnancy due to its possible skin sensitizing effect.	85 – 95%
Cajeput	Cajuput is non-toxic and non-sensitizing, yet could irritate the skin when used in high concentration.	some	Cineol 45-70%
Camphor	Camphor oil is powerful and should be used with care. Overdosing can cause convulsions and vomiting. Pregnant women or persons suffering from epilepsy and asthma should not use it.
Cardamon	Non-toxic, non-irritant, non-sensitizing.	some	High
Cinammon	Cinnamon leaf oil is non-toxic, yet since the cinnamaldehyde and eugenol could cause irritation, and irritation to mucus membranes, it should be used with care. High dosages can cause convulsions and should be avoided during pregnancy.	None recorded	None recorded
Cinnamon bark oil	This should never be used in henna application, the oil extracted from the bark is a dermal toxin, irritant and sensitizer and must never be used on the skin.	None recorded	None recorded
Clove	Clove oil can cause dermatitis and irritate the skin and mucus membranes.
Clove Bud	Clove Bud oil is also very potent oil and should be used with care. It is a skin irritant and should not be applied to the skin. It must be avoided during pregnancy.
Cypress	The oil is considered non-toxic, non-irritant and non-sensitizing but is best to avoid during pregnancy and is best to do a skin patch test before using it on skin.	High
Cypress tips	No data available
Eucalyptus General advice	Eucalyptus oil is toxic and should be used with care, people with high blood pressure and epilepsy should avoid it. Excessive use of the oil may cause headaches.
Eucalyptus citriodora	Toxic by ingestion	15 – 20%	40 – 80%
Eucalyptus dives	Toxic by ingestion	-	-
Eucalyptus globulus	Toxic by ingestion	10 -12 %	Cineol 70 – 75 %
Eucalyptus polybractea	Toxic by ingestion	-	Cineol 10 %
Eucalyptus radiata	Toxic by ingestion	8 – 20 %	Cineol 62 - 72 %
Frankinsense	non-toxic and non-irritant and could be used by most people	40 %
Geranium	Geranium oil is not indicated to cause any side effects since it is non-toxic, non-irritant and generally non-sensitizing, although it is contraindicated for Hypoglycemia. As with all essential oils it can cause sensitivity in some people and due to the fact that it balances the hormonal system, it might not be a good idea to use in pregnancy. This oil is a good insect repellent and is safe for skin application on most subjects.	60 – 68 %
Juniper	It is considered non-toxic but since it can stimulate the uterine muscle it should not be used during pregnancy, nor by people with kidney problems. It is non-sensitizing but some people do have a reaction to it, and it is generally wise to use this oil in moderation.	34 – 46 %
Lavender	Lavender is considered one of the safest essential oils, but allergic reaction is possible and use should be discontinued if any discomfort is noted. *Lavandin oil is often sold as ‘Lavender’ oil but has quite different properties and composition and is unsuitable for use in henna application.	some	some
Marjoram	non-toxic, non-irritant and non-sensitizing but should not be used during pregnancy.	40%	50%
Neroli	non-toxic, non-sensitizing, non-irritant.	35%
Pine	Although pine and pine needle oil are considered safe since they are non-toxic they should still be used with care on the skin since they can cause irritation in subjects prone to allergic skin reactions or during pregnancy.	25 – 30%
Ravensara	This is a mild oil, safe for most people but should be avoided in pregnancy	High
Rosmary General	Rosemary oil should not be used during pregnancy and is unsuitable for people with epilepsy or high blood pressure.
Rosmary Cineol		12%	High
Rosmary Verbenon		15 – 30%	Cineol up to 20%
Thyme General	Thyme oil is a very potent oil and should not be used during pregnancy or in cases of
Thymus Vulgaris	Thymus Vulgaris is a skin irritant, it should not be used with epileptic conditions, hyperthyroidism, high blood pressure or during pregnancy	High
Red Thyme	Red thyme contains a high amount of toxic phenols (carvacrol and thymol) which can irritate mucus membranes, cause skin irritation as well as skin sensitization.
White Thyme	When using white thyme oil it is imperative to do a skin patch test to determine if the person is sensitive to the oil.
Tea Tree	Tea Tree oil is usually without any contra-indications but it may cause sensitization in some people. The strength of Tea Tree oil should be respected and therefore large amounts should never be used neat on the body or in particularly sensitive areas.

Table 3 Essential oils for henna safety data

This table gives safety data for commonly used essential oils. It is not an exhaustive resource. Where possible an artist should always check the safety data for their essential oils with a number of sources. Where available chemical data* has been included.

* Chemical data pertains to terpene and monterpene content in the oil shown to be effective in darkening henna stains in skin. Based upon the research work of Catherine Cartwright Jones.