Essential Oils Guide: Benefits, Uses, and Safety Tips
Holistic HealthAromatherapy & Essential Oils

What Are Essential Oils? A Complete Guide on Aromatherapy and Its Potential Health Benefits

What Are Essential Oils? A Complete Guide on Aromatherapy and Its Potential Health Benefits
Everyday Health
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Updated on February 6, 2026
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Essential oils are potent, fragrant plant extracts added to lotions, household cleaners, massage treatments, and even integrative complementary therapy to manage cancer symptoms. They’re thought to improve sleep, lessen anxiety, reduce pain, and ease nausea. But how do they work? Learn about the potential health benefits of essential oils here, plus other safety considerations.

History of Essential Oils

Early records suggest that essential oils came from ancient India, Persia, and Egypt. But they’ve been used for centuries by many cultures.

 Ancient Egyptians used them in cosmetics and ointments as early as 4500 B.C. Traditional Chinese and Indian medicine relied on them for healing between 3000 and 2000 B.C.

But aromatherapy — the practice of using aromatic materials for wellness — has been around for centuries. These oils were called “essential” because they were thought to represent the essence of odor and flavor from the plant sources from which they were derived.

French chemist René-Maurice Gattefossé is credited with founding the science of aromatherapy in the Western world in the 1920s, drawing upon its ancient, global roots. He began analyzing the chemical properties of essential oils after using lavender oil to heal a burn on his hand.

Despite essential oils’ long history and widespread use, scientists are still trying to understand how they work to promote health. Researchers are studying their effects on stress, pain, nausea and vomiting, sleep, anxiety and depression, and more.

How Essential Oils Are Derived and How They Work

Essential oils are made by steaming and pressing various parts of a plant to capture the compounds that give the plant its unique fragrance. These oils can be breathed in, added to a carrier oil for direct use on the skin, taken by mouth (some, not all), or used in household products to clean and sanitize.

When inhaled, the molecules in essential oils travel up the nose and interact with scent receptors, which stimulate the olfactory nerve that connects to the brain.

“The oil itself doesn’t go up into the brain, but it stimulates a response that typically affects different aspects of the brain and the central nervous system, specifically in regions called the limbic system. This system has a lot to do with arousal, memory, and processing emotions,” says Michelle Davila, ND, who has retired from clinical practice.

Scientists believe lavender use, for example, has a sedative effect on the brain. But larger, more extensive studies are needed on its long-term effects, especially for those using it to help relieve symptoms of neurological or mental health conditions.

Essential oils are also effective by putting them on skin. “Because of their low molecular weight and the fact that they’re fat-soluble, essential oils can get into the bloodstream and affect different aspects of our overall health,” says Dr. Davila. But whether you’re breathing them in or putting them on your skin, the effects are fairly similar, she adds.

Most people use essential oils at home, but they’re also used in a variety of healthcare settings. For example, sometimes aromatherapy is incorporated into massage therapy for osteoarthritis knee pain, anxiety, and other symptoms in people with cancer.

Doctors, nurses, chiropractors, acupuncturists, holistic healthcare providers, and dentists may also use them, says Shanti Dechen, a certified clinical aromatherapy practitioner, licensed massage therapist, and director of Aroma Apothecary Healing Arts Academy in Crestone, Colorado.

The practice of aromatherapy and manufacturing of aromatherapy products are not regulated in the United States, and aromatherapists aren’t required to be licensed or certified. However, many organizations do offer education and certification programs, such as the National Association for Holistic Aromatherapy (NAHA).

Ways to Breathe In Essential Oils

The most common way to use essential oils is to breathe them in by using a diffuser, dry evaporation, aroma sticks, or steam.

Diffusers

Diffusers are devices that break essential oils down into smaller molecules and send them into the air. Some diffusers use water and heat so that the oils evaporate.

Aroma Sticks

Aroma sticks, also known as essential oil inhalers, are portable plastic devices with an absorbent wick at one end. The wick soaks up the essential oil, while the cover protects the scent until you’re ready to remove it for a sniff. You can carry aroma sticks with you to inhale throughout the day.

Dry Evaporation

Dry evaporation is exactly what it sounds like: using a dry material to release the scent of an essential oil. Simply place several drops of essential oil on a cotton ball, tissue, or other absorbent material, like terra cotta, and allow it to evaporate into the air. You can sniff the cotton ball or keep it nearby.

Steam

Davila recommends steam inhalation to her clients. This method involves boiling a pot of water, removing it from the heat, adding three to five drops of an essential oil, and placing your face over the pot to inhale the steam.

Hot water quickly vaporizes the essential oil, which is mixed with the rising steam. Be sure to take the pot off the stove and let it settle before leaning over it. Use caution when touching the pot, too. Place a towel over your head to slow the release of steam, close your eyes, and breathe normally.

This will get the essential oil compounds into your lungs and respiratory tract, Davila says.

Essential Oil Application to Your Skin

Applying essential oils directly to your skin — via massage, bath, or a skin care product — is another common method. But it’s important to note that most essential oils should not be applied directly to the skin without diluting them first.

Topical essential oils are mixed with carrier oils like jojoba, coconut, or olive oil to aid absorption, provide additional vitamins, and protect your skin against allergic reactions.

 Other common carrier oils include sweet almond oil, apricot kernel oil, or grapeseed oil.

“Carrier oils make essential oils a lot safer, because what they’ve found over years of research is that if you apply an essential oil [that’s] undiluted, it will create allergic reactions in many people over time,” Dechen says.

To dilute essential oils, use a carrier oil at a concentration no greater than 1 percent when used in massage oil, or one drop of pure essential oil for every 1 teaspoon (tsp) of carrier oil.

Can I Eat or Vape Essential Oils?

Technically, essential oils can be ingested and vaped, but experts warn that these approaches can be very dangerous.

“Ingesting essential oils in water or capsules is something that requires advanced knowledge and training to do,” Davila says. Typically, the drink or capsule has to be specially formulated and diluted to the proper degree. You also have to know how much to ingest and for how long, and which ones are safe. Ingesting essential oils the wrong way can irritate your esophagus and stomach, or worse, be toxic, Davila warns.

Drinking essential oils in a glass of water will send molecules right into the membranes of your mouth, which, “over time, it [can] create scar tissue and irritation,” Dechen says.

Vaping — inhaling and exhaling a vapor via a vape pen, similar to an e-cigarette device — is also a potentially dangerous way to use essential oils. “Currently, there’s no real research available on the effects of vaping essential oils,” Dechen says. While essential oils are generally considered safe to breathe in, heating them with the metal coil inside the vape pen has the potential to change their chemistry and become toxic when inhaled into your mouth, throat, and lungs, she says. Bottom line: Do not vape essential oils.

Possible Health Benefits of Essential Oils

Essential oils can affect your brain and travel through your bloodstream to offer potential health benefits, including:

Less Anxiety

Dechen says people use aromatherapy to ease anxiety. A meta-analysis found that lavender aromatherapy helped relieve anxiety and depressive symptoms in participants, although more studies are needed to determine the best method of administration, time frame, and dosage.

Lavender essential oil is thought to contain compounds that interact with the limbic system, the part of the brain that regulates your emotions. When inhaled, lavender exerts a relaxing effect, though much of the research has been done in test tubes and on animals.

Other essential oils that may lower anxiety include lemongrass, orange, bergamot, and cedarwood.

Better Sleep

Because essential oils can have a relaxing effect, they may also help you sleep better. A meta-analysis found that older adults who used aromatherapy for four weeks had improved sleep quality, reduced stress and pain, and less fatigue. The method for aromatherapy delivery was not noted, however.

A small pilot study also found that use of lavender oil increased the production of delta waves during sleep. Those are the slowest brain waves that happen during restorative sleep. But this study only included nine participants, meaning more research is needed to determine this effect.

Most research regarding sleep and essential oils is done in short periods with small groups of people. Long-term, extensive research is needed to truly understand how lavender (and all essential oils) can help with sleep quality.

Reduced Nausea

Essential oils like peppermint and ginger may help relieve nausea. Studies show that inhaling peppermint oil, for example, reduces nausea and vomiting in people getting cancer treatments.

Meanwhile, ginger use can help speed up digestion and reduce the effects of functional dyspepsia (chronic indigestion) like gas, abdominal pain, and heartburn.

Keep in mind that these studies only tested peppermint and ginger for people with particular gastrointestinal disorders. Using these essential oils may not have the same therapeutic effects on digestion for everyone.

Essential Oils Safety and Side Effects

Just because essential oils come from plants doesn’t mean they’re totally safe. “There are definitely safety concerns,” Davila says. “Essential oils are so concentrated that, sometimes, one drop of an essential oil is like an ounce or more of the plant material.”

For some people, use of essential oils can irritate the skin even if applied with a carrier oil. Allergic reactions to certain oils are also possible, including:

  • Oregano oil
  • Cinnamon bark oil
  • Jasmine oil
  • Lemongrass oil
  • Ylang-ylang oil
  • Chamomile oil
  • Bergamot oil
Use caution when applying essential oils if you have allergies or sensitive skin. Always dilute them with a carrier oil, and test it out on a small part of your skin first to see if a reaction happens. This is known as patch testing.

Some essential oils are photosensitive, meaning they can make your skin more sensitive to sunlight and cause redness, discoloration, or blistering. These include:

  • Bitter orange peel
  • Mandarin leaf
  • Lemon peel
  • Lime peel
  • Cumin seed
  • Grapefruit peel
  • Bergamot peel
  • Rue leaf
  • Angelica root

Davila recommends avoiding direct sunlight for 12 to 24 hours after using one of these oils on your skin.

Why Young Children Should Avoid Certain Essential Oils

Very few studies have looked at essential oil use in children. While some older research found that essential oils could disrupt children’s hormone production, newer findings suggest this is likely untrue.

One study found that children exposed to lavender and tea tree oil, for example, had the same risk of developing endocrine disorders as those who weren’t exposed.

Because the research is mixed, talk to your child’s pediatrician before using essential oils at home, especially lavender and tea tree oil. Davila recommends avoiding using them daily at high doses. Occasional use (one or twice a week) for a short period of time (several weeks) may be fine for adults.

Who Might Want to Try (or Avoid) Essential Oils

Essential oils show promise as a therapeutic method for a wide range of health concerns, including anxiety, sleep issues, nausea, and pain. But they’re not right for everyone.

Pregnant women, for example, should speak with a healthcare provider before using essential oils, as certain types may be able to travel into the womb.

“Typically, it’s recommended not to use them during the first trimester. If you use them in the second or third trimesters, limit yourself to the floral or citrus oils and use them for aromatherapy versus topical use,” Davila says.

People with allergies, sensitive skin, or long-term health conditions should avoid essential oils or be cautious when thinking about trying them, Davila warns.

Use of essential oils can also negatively affect certain medications. Frankincense oil (Boswellia), for example, may affect blood-thinning medications like warfarin.

 So check in with your doctor before trying any new aromatherapy treatments like essential oils.

Infants and children younger than 5 should also not use essential oils, Dechen says.

Tips for Getting Started With Essential Oils

Before you start using essential oils, think about why you want to use them and which oils you'd like to try. If your goal is better sleep and stress relief, you might opt to use calming oils like lavender, chamomile, basil, or frankincense. Meanwhile, use of stimulating oils like bergamot and peppermint might be best for those with low energy.

Choosing an essential oil is highly individual, so you may benefit from talking with a qualified aromatherapist. They can tell you when and how often to use the oil based on your goal. They can also check for any potentially harmful effects that using your desired oils might cause you.

Purchase high-quality essential oils online or at a holistic healthcare store. (Grocery stores and supplement stores often sell essential oils, too.) Do your research on brands and products to ensure the oils are high-quality. Here are a few key things to look for:

  • The Latin name of the plant
  • The name of the country where the plants were grown
  • A statement about the purity of the oil
You should also figure out what application method you’d like to use. Inhalation via diffuser, steam, bath, aroma stick, or dry evaporation tends to be less irritating to the skin and works faster than topical applications.

The Takeaway

  • Essential oils, derived from plant extracts, have been used for centuries in ancient medicine practices around the world. Their potential health benefits include reduced anxiety, improved sleep, less pain, and better digestive health.
  • There are several different ways to use essential oils, including aromatherapy, massage, inhalation, and more.
  • More research is needed surrounding essential oils and their effectiveness at treating and healing various health conditions. Larger, long-term studies are needed to determine ideal dosages, time frame, and method of administration for various ailments.
  • Talk to your doctor before using essential oils, especially if you have sensitive skin or allergies, have underlying health conditions, or take certain prescription medications.

Resources We Trust

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
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Grant Chu, MD, is an associate clinical professor at the David Geffen School of Medicine at UCLA. Dr. Chu is also associate director of inpatient East-West consult services at the UCLA Health hospitals.

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