J Clin Nurs. 1999 May; 8(3): 299-304.

How big is a drop? A volumetric assay of essential oils.

Olleveant NA, Humphris G, Roe B.

Intensive Care Unit, Royal Liverpool University Hospital, UK.

There has been an increase in the use of aromatherapy in nursing, and many issues are now being raised which need addressing in order to maintain professional credibility and safe practice. These issues include: who can safely practise aromatherapy, what qualifications are required to practise, who provides indemnity, and other issues, including the safety and toxicity of essential oils. A small study was undertaken to examine the differences in drop size of bergamot essential oil. Drop size was determined by weighing different manufacturers' essential oil of bergamot and it was found that drop size did differ, resulting in unequal doses of essential oil. It is important to be aware of this, because there are implications for the size of the dose administered in an aromatherapy treatment. This paper raises the issue of standardizing the measurement of essential oils, to ensure that there are no problems regarding safety in their administration.