Volatile oil is a term for the aromatic, readily evaporating mixture of compounds found in certain plants.
These oils are commonly called essential oils because they carry much of the characteristic aroma—or “essence”—of the plant.
Unlike fixed oils such as olive or sunflower oil, volatile oils readily evaporate and usually do not leave the same persistent greasy residue.
How the Term is Used
In herbalism and botany, volatile oil refers to the aromatic oil naturally present in plant tissues.
These oils may occur in flowers, leaves, peel, bark, roots, seeds, or other plant parts, depending on the species.
Peppermint, lavender, rosemary, thyme, eucalyptus, citrus peel, and many culinary spices contain volatile aromatic compounds.
The term describes a type of plant constituent, not one particular action.
Volatile Oil vs. Essential Oil
In many contexts, the terms volatile oil and essential oil refer to the same general category of aromatic plant oils.
WHO notes that volatile oil is the more physically descriptive term because these compounds readily evaporate.
“Essential” does not mean nutritionally essential.
It refers historically to the plant’s aromatic essence.
That distinction saves a surprising amount of confusion.
How Are Volatile Oils Obtained?
Many essential oils are produced through steam or water distillation.
During distillation, heat and steam release volatile compounds from the plant material. The aromatic compounds travel with the steam, are cooled back into liquid, and then separate from the water.
WHO identifies water and steam distillation as common methods for extracting volatile constituents from herbs. Some oils may instead be obtained through methods such as expression, particularly with citrus peel.
Volatile Oil vs. Fixed Oil
These are very different types of plant oils.
Volatile oils readily evaporate and are primarily associated with plant aroma.
Fixed oils—such as olive, sunflower, almond, or coconut oil—are composed largely of fatty acids and do not readily evaporate at room temperature.
A fixed oil may even be used as a carrier oil to dilute a concentrated volatile oil for topical use.
The Whole Herb Is Not the Essential Oil
Peppermint leaf and peppermint essential oil both come from the same plant.
They are still very different preparations.
An herbal infusion contains water-soluble constituents from the leaf along with a portion of its aromatic compounds.
A distilled essential oil concentrates the plant’s volatile fraction.
EMA, for example, defines medicinal peppermint oil specifically as essential oil obtained by steam distillation from the fresh flowering aerial parts of Mentha × piperita.
So research on peppermint tea should not automatically be applied to peppermint essential oil—or vice versa.
Same plant. Very different concentration and preparation.
Why Cover Aromatic Infusions?
Here is where volatile oils connect directly to our Infusion and Herbal Infusion pages.
If an aromatic plant is steeped uncovered, some volatile compounds can escape with the steam.
That is why aromatic herbal infusions are often covered while steeping.
If the part you want smells wonderful and escapes with the steam…
maybe don’t let all the steam escape.
Drying, Crushing & Storage Matter
Because volatile compounds evaporate readily, how aromatic herbs are handled can affect them.
Drying conditions, heat, storage time, crushing, and exposure to air can all influence aroma and volatile-oil content.
WHO even notes that preparation of plant material for volatile-oil testing depends on where the oil is stored within the plant; excessive crushing can sometimes allow easily released oils to escape.
That is one reason freshly crushed herbs can smell much stronger:
you just released more volatile compounds into the air.
Concentration Matters
An essential oil is far more concentrated than the amount of volatile oil naturally present in a cup of tea or a small amount of culinary herb.
That concentration changes how it should be handled.
NCCIH notes that essential oils used in aromatherapy are commonly inhaled or applied to the skin in diluted form, and that topical use can sometimes cause irritation or allergic reactions.
So:
“It came from a plant” does not mean “use it the same way you would use the plant.”
Aromatherapy & Herbalism
Volatile oils are commonly used in aromatherapy, which NCCIH defines as the therapeutic use of essential oils from plants.
Herbalism and aromatherapy overlap, but they are not identical.
Herbalism may use whole plants, teas, tinctures, powders, poultices, oils, and many other preparations.
Aromatherapy focuses specifically on concentrated aromatic plant oils and their use.
Safety & Considerations
Essential oils are highly concentrated botanical preparations.
Some can irritate skin, trigger allergic reactions, or require substantial dilution. Certain oils also have specific cautions depending on the plant and route of use.
For example, NCCIH notes that topical peppermint oil can cause skin irritation and should not be applied to the face of infants or young children because inhaled menthol can cause serious effects.
The useful questions remain:
Which oil? How concentrated? How is it being used?
Related Terms
Related concepts include Infusion, Herbal Infusion, Decoction, Tincture, Maceration and Bioavailability. These terms connect through botanical constituents and preparation methods, but each has its own meaning and context.
How to Evaluate Volatile-Oil Claims
When a product or study refers to a volatile or essential oil, consider which plant and plant part were used, how the oil was produced, its concentration, how it was administered, and whether the evidence actually involved that specific oil preparation.
Research on the whole herb should not automatically be applied to the essential oil.
And research on one essential oil should not be generalized to all essential oils.
Why Context Matters
Volatile oils help give aromatic plants their distinctive scent.
But once those compounds are isolated and concentrated into an essential oil, the preparation is very different from the original herb.
Understanding volatility, extraction, concentration, and preparation helps explain why peppermint leaf, peppermint tea, and peppermint essential oil may all come from the same plant but should not be treated as the same thing.
A Note on Wellness Language
Wellness terms can change over time and may be used differently across botanical, scientific, traditional, and commercial settings. Our goal is to explain them clearly and give enough context for you to make sense of the language you encounter.
Explore Related Terms
Continue through the Herbal & Wellness Glossary to explore related plant constituents, preparation methods, and wellness concepts.
A Note on Educational Information
The information in this glossary is provided for educational purposes only. It is intended to explain terminology and provide context, not to diagnose, treat, cure, or prevent disease, or replace advice from a qualified healthcare professional.
Return to the Herbal & Wellness Glossary
Return to the Herbal & Wellness Glossary to explore more terms, preparation methods and wellness concepts used throughout the site.
Smell the plant. Follow the chemistry. Respect the concentration. 🌿💧