Essential oils vary in their characteristics and each person is different in how they may respond to using them. The most common unwanted result is skin irritation. Some oils are ‘hot’ and may cause irritation especially on sensitive areas or those with sensitive skin.  To avoid such situations it is always prudent to dilute oils with a carrier and to perform a basic skin test. Use only the pure therapeutic grade essential oils which  have been tested for impurities.

Basic Skin Test
Place a small amount of carrier oil such as coconut or olive oil, followed by a small amount of the essential oil on the inside of the elbow, underside of the forearm, or wrist.  After approximately 1 hour, check the area(s) for any type of reaction.

Some Essential Oils Are Photosensitive.

Some oils are photosensitive meaning they react to light such as natural sunlight, sunlamps, or other sources of UV rays.  An adverse response appears within minutes, hours, or days after first application and exposure.  These oils are primarily citrus oils and include angelica, Bergamot, Grapefruit, Lemon, Lime, Orange, Wild Orange, and tangerine.  The result is a dark pigmentation or a rash on the skin. When using photosensitizing oil, wait a minimum of 12 hours before exposing skin to UV rays.

Use Care with Babies and People with Sensitive Skin. 

Increased watchfulness should be used when treating babies, young children, and the elderly.  Their skin is much more sensitive and susceptible to irritation, burning, or stinging sensations. Using an effective carrier oil will protect sensitive skin against irritation.

Use Care with Eyes, Ears, etc.

Never apply oils directly to the eyes or ear canal.  After application, be attentive to things like rubbing the eyes, areas around the eye, eyelids, handling contact lenses.  The skin is most sensitive and prone to irritation around the genitals and mucous membranes.

Use care when applying oils to infants and children. 

After application the child should be supervised and areas where oils were applied should be clothed until the oils have been sufficiently absorbed to protect from cross contamination.  A baby might easily grab their foot after oils were applied and then rub his or her eyes.


Aromatherapists generally agree that no oils topically (externally) applied at ordinary amounts have ever proven harmful to a developing fetus.  However, pregnant women might want to consult a physician or licensed aromatherapist prior to using essential oils.  If there are specific oils that pregnant women should be concerned about, it will be noted on the oil bottle from most reputable suppliers.  Cautious about using essential oils during pregnancy, especially during the first trimester. Even oils that are generally safe during this time may be too stimulating for women who are prone to miscarriage.

Critical Health Conditions. 
Persons with asthma, epilepsy, high blood pressure, or other critical health conditions can benefit from essential oils, but should consult a healthcare or aromatherapy professional when addressing these serious conditions.

Oils Not Suitable for Use in Aromatherapy. 

Caution or consultation should be used before using wormwood, pennyroyal, camphor, sassafras, onion, bitter almond, and horseradish.  Ruta gravenolens or rue essential oil is classified as poisonous to humans and should not be used.

A Little Goes a Long Way. 

There is a reason for the drip hole in top of oil bottles.  All essential oils are pure concentrates.  The higher quality the oil the more potent it is and smaller amounts are required.


Most essential oils are safe for ingesting.  The oils section of this book will note if an oil is GRAS, generally regarded as safe by the FDA.   If ingesting, consider diluting it in a water, agave, honey, or juice.

Keep Out of Reach of Children. 
Treat essential oils the same as medicine.  Oils can be painful or harmful if used in the eyes or if large quantities of the wrong oil are ingested.

Essential Oil and Bath Water. 
One common application method is use of a bath.  Full body, foot or hand baths are all common.  When using undiluted oil in bath water, agitate the mixture because the oil can pool as a concentrated drop in one spot in the water.  You can also use a dispersing gel.  Oils will evaporate very quickly in hot water.  If you want to enjoy a hot bath, start it hot, then add the oils and agitate the water after the temperature has gone down.

Many Oils Are Flammable.

Keep them clear of open flame, spark, or Fire hazards.