What Are Essential Oils?
What essential oils are, how they are made, what they contain, and why "natural" does not mean safe. A plain-language introduction with safety up front.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Safety first. Essential oils are strong. Do not swallow them, do not put them undiluted on skin, and keep them away from young children and pets. See Essential oil safety.
What they are
Essential oils are concentrated plant extracts that keep the natural smell and flavor of their source. They are obtained by mechanical pressing or by distillation. [1] NIH's NCCIH describes essential oils as very concentrated oils containing the substances that give a plant its characteristic odor or flavor. [2] Synthetic oils are not considered true essential oils. [1]What they contain
Each essential oil has its own mix of chemicals, and that mix affects the smell, how it is absorbed and how it acts on the body. The mix can even vary within the same plant species, or from plant to plant. [1] This is why a result found for one oil cannot be assumed for another, or for a different batch.Essential oil vs plant vs supplement
An essential oil is not the same thing as the herb it comes from, a tea, or a capsule. Their composition, how they are used, the research and the risks can all differ. Peppermint oil, for example, is distinct from peppermint leaf tea in the NIH summary. [2]Natural does not mean safe
The FDA points out that many plants contain materials that are toxic, irritating or likely to cause allergic reactions on the skin. Cumin oil is safe in food but can cause the skin to blister, and certain citrus oils used safely in food can be harmful in cosmetics, particularly on skin exposed to sun. [3] The FDA has no regulations defining "natural" or "organic" for cosmetics. [3]Names matter
Use the botanical name when comparing products, because common names can cover more than one plant. For example, tea tree oil comes from Melaleuca alternifolia. [4] See the directory and label guide.What this website does not do
We do not give mixing charts, recipes, or advice to swallow oils. Where research exists, we describe it, and where it does not, we say so. See Aromatherapy and Essential oils by wellness goal.Frequently asked questions
Are essential oils the same as aromatherapy?
No. Essential oils are the products. Aromatherapy is a practice that uses them, most often by inhaling them or by applying a diluted form to the skin. [5]
Are essential oils safe because they are natural?
No. The FDA says plant origin does not make an ingredient safe. [3]
References
- National Institute of Environmental Health Sciences (NIH). Essential Oils. Last reviewed March 19, 2026.
- National Center for Complementary and Integrative Health (NIH). Peppermint Oil: Usefulness and Safety. Page last updated May 2025.
- U.S. Food and Drug Administration. Aromatherapy. Content current as of September 8, 2023.
- National Center for Complementary and Integrative Health (NIH). Tea Tree Oil: Usefulness and Safety. Page last updated April 2025.
- National Center for Complementary and Integrative Health (NIH). Aromatherapy. Page last updated January 2020.