Safety, Dilution and Use

What essential oils are

Essential oils are concentrated volatile oils taken from plant material, and the concentration that gives them their aroma and effect is far higher than the level at which they are safe on skin, so they must always be diluted before use.

Never apply an essential oil undiluted to the skin, to broken skin or near the eyes. The rates below are general guidance for healthy adult skin; the safety data sheet takes precedence.

Dilution rates

Working maximums for healthy adult skin: face and body, 1 to 2%; facial care and around the eyes, 0.5% or less; a standard room diffuser load, 1%. Products for babies, children, pets and intimate areas need a lower rate.

Worked example: 2 drops of oil, roughly 0.1 ml, mixed into about 5 ml, one teaspoon, of carrier oil gives approximately 1%. For a 1% blend, use 1 ml of oil to 99 ml of carrier; always measure, and add the oil to the carrier.

Patch testing

Patch test before using a new oil or blend over a wide area: apply the diluted product to skin on the inside of the forearm or behind the ear, leave it 24 to 48 hours, and check for redness, itching, swelling or blistering.

If a reaction occurs, wash the area with a carrier oil and mild soap, stop using the product, and seek advice from a pharmacist or doctor. A patch test cannot rule out every sensitivity.

Named sensitisers and EU labelling thresholds

Fragrance allergens named in Annex III of EU Regulation 1223/2009 must be declared on the label when present above 0.001% in a leave-on product or 0.01% in a rinse-off product; those relevant here are limonene, linalool, citral, geraniol, citronellol, eugenol, iso-eugenol, coumarin, cinnamal and farnesol.

Many of these occur naturally in essential oils, so a botanical product may need a declaration just as a synthetic blend does; the thresholds apply to the finished product as placed on the market, and whoever places it there carries that responsibility.

Who should seek medical advice first

Consult a doctor before using essential oils if you are pregnant or breastfeeding, for a child, or if you or a family member have epilepsy, asthma, diabetes, a skin condition, a history of allergy, or are undergoing chemotherapy or immune treatment; some people should avoid them altogether.

This list is not exhaustive: if you have a medical condition or take regular medication, ask a doctor or pharmacist before you buy.

Household and pet safety

Never diffuse essential oils around birds, because several oils are fatal to birds and other small pets. Keep products out of reach of children and animals, never diffuse in poorly ventilated rooms, never mix oils with cleaning products, never ingest them, and never use them in the eyes or on broken skin.

Essential oils are flammable: keep them away from heat, hot surfaces, flame and sparks, and never place a diffuser on or near a heat source. Do not pour an oil into a water-based appliance such as a humidifier unless it is designed for that oil and solvent.

Storage and shelf life

Store bottles tightly closed, upright, in a cool place away from direct light and out of reach of children and pets. Use within 12 months of opening, and 24 to 36 months of manufacture while unopened.

Oxidation shows as a change of colour, a loss of strength or a stale, off or unusual smell; if you notice any of these, stop using the oil and dispose of it. If you are unsure whether a bottle is still good, replace it.

Spills, skin contact and first aid

Do not use water to wash concentrated oil off skin, because it spreads the oil and drives it deeper: blot the area, remove contaminated clothing, and wash with a carrier oil or other non-water solvent, then mild soap and water. Seek medical advice if irritation persists, and contact your local poison centre if oil has been swallowed.

For a spill on a surface, blot it up promptly, ventilate the area, and clean it with a carrier oil or alcohol-based cleaner rather than water alone; never leave an open bottle unattended.

Irritation and chemical burns

Some aroma materials are irritants, and a concentrated essential oil can cause redness, burning, blistering or a deeper chemical injury on prolonged contact; coumarin and eugenol in particular are known sensitisers, and repeated exposure raises the likelihood of a reaction. Contact that causes pain or blistering is a medical matter.

Do not treat a burn with an oil or a home remedy; seek medical advice promptly, and take the bottle with you so the healthcare professional can see the product and its label.

Biosynthetic aroma molecules are not essential oils

The biosynthetic aroma molecules sold on this site are produced by fermentation and biocatalysis. They are not essential oils or botanical extracts, and must not be described or marketed as natural essential oils.

Being manufactured rather than distilled does not make a material harmless: a biosynthetic molecule can still be a named Annex III fragrance allergen and can still irritate or sensitise. Read the documentation supplied with it, dilute as directed, and handle it as any concentrated material.

Disclaimer

This page is general guidance on the safe handling and dilution of aroma materials. It is not medical advice, and does not replace the safety data sheet, the IFRA conformity statement, or advice from a qualified doctor or pharmacist.

We cannot take responsibility for misuse, including use at an undiluted concentration, on broken skin, by ingestion, or where medical advice was needed and not sought. If you are uncertain, stop and ask us or a healthcare professional.