Daniele Ryman
Aromatherapy Bible

Aromatherapy & Aromacology

Toxicity Of Essential Oils

Certain constituents of essential oils are very toxic, particularly to vulnerable people like the old, the very young, and pregnant women. On the whole, this toxicity of essential oils applies to an oil when taken internally, which is something I am passionately against. Certain of these toxins in certain oils can be dangerous when applied externally (or inhaled), and I have given clear warnings where necessary throughout the book. In many cases, though, because of a balance of constituents in the oil, or because of a balance of more than one essential oil in a remedy (or even just because of the calming influence of a certain carrier oil), the oil can still be used safely. It is usually only when potentially dangerous oils are used in too large quantities that the dangers become a reality and for this reason the proportions of essential oils recommended must be respected. One must remember that one little drop of an essential oil represents between 25 and 35 g (1 and 1 1/4 oz) of the plant itself. Proportion is the key to everything.

The International Fragrance Association (IFRA) has addressed the potential problem of the toxicity of essential oils. It has issued a list of oils whose use is restricted in the industries which use fragrancies in their products, for example cosmetics and household products. IFRA gives these oils strict proportion controls and of those used in aromatherapy they include angelica root, baume de Perou, bergamot, cinnamon cassia, cumin, sassafras and verbena. IFRA has no international legal powers, but most fragrance companies worldwide do follow their guidelines.

In addition to those oils restricted by IFRA, I consider the following to be worthy of close and careful attention: anise, aspic, basil, clove, coriander, hyssop and sage. These worries mostly concern constituents such as anethol, estragol (methyl-chavicol) and thujone, but I'm also careful about those containing eugenol (which can corrode metal).
Toxic reactions can be felt immediately, and range from dizziness and nausea to exhaustion, epilepsy and even death. Some toxins cause allergy: the tansy flower, used in perfumery (and now restricted in the industry by the French Ministry of Health), has caused terrible eczema on the hands of the pickers.

Pregnancy

I don't advise anyone who is pregnant to use any essential oils. Not only does the skin become more sensitive during pregnancy, but some women find that smells they once had no problems with now make them feel nauseous or irritable. More alarmingly, certain essential oils, particularly those containing apiol and myristicine, have abortive powers and cause miscarriage or have other undesirable effects on the womb. Parsley, for example, in very large doses was once used as an abortive. In France apiol was used in contraception before the advent of the pill, and in South America it is still used today.

Instead of using the essential oils, try very weak herbal teas, in small quantities, and bring aromatherapy into your life in other ways - for instance by bringing flowers into your home, by using the relevant herbs in cooking, or using weak infusions of the plants themselves.
If you think you may be pregnant, do stop using essential oils immediately, and of course always consult your doctor.