There are many operant definitions of aromatherapy, and some of them contribute to common misconceptions. The word aromatherapy can lead people to believe that it simply involves smelling scents but this is incorrect. It is important to remember that the widespread use of synthetic scents in household and personal products is not considered aromatherapy. Styles (1997) defined aromatherapy as the use of essential oils for therapeutic purposes that encompass mind, body, and spirit—a broad definition that is consistent with holistic nursing practice. The National Cancer Institute defines aromatherapy as the “therapeutic use of essential oils from flowers, herbs, and trees for the improvement of physical, emotional, and spiritual well-being” (National Cancer Institute [NCI], 2012). Buckle defined clinical aromatherapy in nursing as the use of essential oils for expected and measurable health outcomes (Buckle, 2000). Because aromatherapy clinical research is still in its early developmental stages in the United States, the evidence base for using aromatherapy in nursing practice sometimes may be difficult to establish; however, there are findings for and against the use of a number of essential oils, and it is important to evaluate the available scientific data for aromatherapy practice.

Essential oils are obtained from a variety of plants worldwide, but not all plants produce essential oils. For those that do, the essential oils may be found in the plants’ flowers, leaves, stems, bark, roots, seeds, resin, or
peels. Most essential oils are obtained by steam distillation of a specific plant material. Steam-distilled essential oils are concentrated substances made up of the oil-soluble, lower-molecular-weight chemical constituents found in the source-plant material. Essential oils from citrus fruit peels are usually obtained by expression (similar to grating or grinding). Carbon dioxide extraction is increasingly accepted by scientists and practitioners as an acceptable method for obtaining essential oils; however, other types of solvent extraction generally are not preferred for clinical use. Expressed and CO₂ extracted essential oils contain a broader range of the chemicals present in the plant material; thus, they may have different therapeutic properties. Essential oils do not necessarily have the same medicinal properties as the plants from which they are derived because they do not contain the whole spectrum of chemicals present in the whole plant.

Nurses have an important role in helping patients to differentiate among the range of botanical products that are easily available. Misunderstanding the origin and makeup of these products can result in unnecessary risk. The most commonly used botanical products can be viewed as a continuum (Exhibit 20.1). On one end of the continuum are whole herbs, referring to unprocessed material from whole plants or parts of plants (Exhibit 20.1, far-right box). This is the oldest and most common form of botanical medicines worldwide. Tinctures and ointments are different from the whole plant and are also different from essential oils (Exhibit 20.1, second box from right). They are often confused with each other, and it is important that nurses understand the difference in order to provide advice on their relative safety. Tinctures contain chemicals obtained from the plant material using alcohol as a solvent, and they include both water-soluble and oil-soluble chemicals. Tinctures are often taken orally or sublingually, with the dose and timing depending on the practitioner and the purpose. They are not as concentrated as essential oils. Ointments are made using vegetable oil (e.g., olive oil) rather than alcohol as the solvent. Plant-based tinctures and ointments are widely available. Flower essences (Exhibit 20.1, second box from left) are also often confused with essential oils. Essences contain little if any of the original plant material, but they are thought to contain the vibrations or frequencies of the plants they are made from. It is the frequency that is considered the source of their therapeutic action, not the physical chemistry. Homeopathy (Exhibit 20.1, far-left box) was developed in Europe and was very popular in the United States in the late 1800s and early
1900s (Dooley, 2002). It declined in popularity as biomedicine became the dominant paradigm. Homeopathic remedies contain no molecules of the materials from which they are made. They are thought to work subtly on a vibrational level to promote balance and healing. Homeopathic remedies may be prescribed by a homeopathic physician or may be obtained over the counter. Homeopathy is becoming more popular in the United States once again; thus, nurses may benefit from understanding its basic concepts and differentiating it from other natural products.