Risks in using essential oils and precautions to be taken

What do essential oils contain?

Essential oils are complex mixtures of substances of natural origin. They are extracted from a plant raw material, usually by steam distillation. Their chemical composition (chemotype) varies greatly depending on the plant’s genus, species and subspecies. It can also vary according to the part of the plant from which the essential oil is extracted (e.g. fruit rind, leaf, stem), as well as the climate, geographical location and harvesting period of the plant. It is difficult to know the exact chemotype of an essential oil sold in a shop.

In addition, many products labelled as “essential oil” actually contain other ingredients, sometimes in concentrations of more than 50%, like some essential oil sprays containing more than 70% of ethanol, or topical oils containing more than 50% of vegetable oil or emollients. 

Can essential oils be dangerous to health?

Essential oils contain substances which, at certain doses, can have health effects. For example, in a 2020 expert appraisal, ANSES identified risks related to food supplements containing tea tree, niaouli and cajeput essential oils. The appraisal confirmed that the oral absorption of certain compounds in Melaleuca essential oils poses neurological (niaouli and cajeput), carcinogenic, genotoxic and potentially reprotoxic risks.

In its toxicovigilance report, ANSES reviewed the number of exposures to essential oils reported to the French poison control centres. Between 2011 and 2021, the number of calls concerning essential oils rose constantly. All were due to adverse reactions linked to domestic accidents and acute poisoning of low severity. In a third of accidents involving children, an essential oil had been administered by mistake instead of a medicine (mainly vitamin D). Data from poison control centres cannot provide information on any medium- or long-term effects.

What precautions should be taken when using essential oils?

All essential oils should be used with caution, but this is especially true for those comprising toxic substances.

• Essential oils are not recommended for children or pregnant women, in particular because they can contain substances that are neurotoxic or toxic for the foetus or embryo. Essential oils should always be kept out of the reach of children;

• They should never be kept with care products for newborns and infants as this increases the risk of confusion between essential oils and vitamin D, in particular;

• Before use, seek the advice of a healthcare professional;

• Comply with the conditions of use;

• When using essential oils in the form of a spray or diffuser, ventilate confined spaces;

• Do not apply undiluted to mucous membranes;

• Wash your hands thoroughly after dermal application or use for massage purposes.

How are the different uses of essential oils regulated?

Essential oils can be used in a wide variety of ways, by dermal application, inhalation or ingestion. They may be used, for example, to purify the air, flavour food or add fragrance to cleaning products.

Several different regulations may apply to essential oils, depending on their use: chemicals, biocides, plant protection products, cosmetics, medical devices, medicines, flavourings or food supplements. Regardless of the regulations that apply, essential oils must never be presented without specifying their function: the establishments responsible for placing them on the market must inform consumers of the method and precautions for use (Article L. 111-1 of the French Consumer Code). It is therefore the intended use (in cosmetics, food, etc.) that determines the applicable regulations and therefore the requirements that the product must meet.