Essential Oils & Aromatherapy
Essential oils are concentrated plant extracts. They smell wonderful and some have been studied, but they are strong substances: they can irritate skin, cause allergic reactions, and be poisonous if swallowed or used around pets and young children. This section starts with what essential oils are, what research has and has not shown, and how to use them more safely.
Each oil has one guide. We keep tradition, laboratory findings and human studies separate, we link a page only when it has real, sourced content, and we do not give recipes, mixing charts or swallowing instructions.
Essential Oil Safety
- Do not swallow essential oils. Tea tree oil taken by mouth has caused confusion, loss of balance and coma.
- Essential oils can irritate skin and cause allergic reactions. Do not put undiluted oil on skin.
- Do not put peppermint oil (menthol) on or near the face of an infant or young child.
- Keep oils away from children and pets. In the US, call Poison Control at 1-800-222-1222 for a person, or the ASPCA Animal Poison Control Center at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661 (a fee applies) for a pet. Call 911 for collapse, seizure or trouble breathing.
Explore essential oils
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Most Searched Oils
The six oils people search for most.
- Tea Tree Oil
- Peppermint Oil
- Lavender Oil
- Rosemary Oil
- Eucalyptus Oil
- Frankincense Oil
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Citrus Oils
Citrus oils.
- Lemon Oil
- Orange Oil
- Bergamot Oil
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Floral & Herbal Oils
Floral and herbal oils.
- Chamomile Oil
- Geranium Oil
- Ylang Ylang Oil
- Clary Sage Oil
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Woody & Resin Oils
Woody and resin oils.
- Cedarwood Oil
- Sandalwood Oil
- Myrrh Oil
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Spice & Strong Oils
Spice and strong oils. Extra caution.
- Cinnamon Oil
- Clove Oil
- Oregano Oil
- Thyme Oil
What Are Essential Oils?
What essential oils are, how they are made and what they contain.
Aromatherapy: Practices & What Research Shows
Inhalation, massage and other practices, and what is known.
Essential Oils by Wellness Goal
Sleep, anxiety, headache, nausea, skin and hair: what the research shows.
Reading Essential Oil Labels & Quality
Botanical names, "pure", "natural" and "therapeutic grade" explained.
Essential Oil Research & Evidence
How much human research exists and how to judge a claim.
Featured guides
Our first oil guides are being written and reviewed. We publish a guide only when it is sourced and ready.
Frequently asked questions
What are essential oils?
Concentrated plant extracts that keep the natural smell and flavor of their source, made by pressing or distillation. [1] See What are essential oils.
Are essential oils safe?
Not automatically. They can irritate skin, cause allergic reactions, and some are poisonous if swallowed or used around pets. See Safety. [2]
Do essential oils work?
It depends on the oil and the goal, and for many uses the research is limited. See by wellness goal.
Can I swallow essential oils?
We do not give advice to swallow any essential oil. Tea tree oil taken by mouth can cause confusion, unsteadiness and coma. [3]
References
- National Institute of Environmental Health Sciences (NIH). Essential Oils. Last reviewed March 19, 2026.
- 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.
Content last updated . This section has not been medically reviewed.