In general, when used properly essential oils are quite safe and highly beneficial. However, because their uses are still relatively unknown, people can and do harm themselves by using these highly concentrated botanical substances improperly.
Toxicology and Safety
- Do not use essential oils internally.
- Do not apply directly to skin; always dilute with carrier oil.
- Keep out of reach of children.
- Avoid contact with eyes and mucous membranes.
- Do not use citrus oils before exposure to UV light.
- Use only pure essential oils; avoid synthetic fragrances.
- Do not use essential oils on infants, children, pregnant women, the elderly, or those with serious health problems, without advanced study.
- Avoid prolonged exposure without ventilation.
- Store essential oils and carrier oils properly to avoid degradation and rancidity.
Do not use essential oils internally:
There are two exceptions to this rule.
The first is properly administered dosages of essential oil medications prescribed by a licensed physician. This is now occurring in certain European clinics, but is rarely available in the US. People should avoid using essential oils internally if prescribed by a lay practitioner, especially if the practitioner’s education is primarily from the marketing perspective rather than clinical.
The second exception is biocompatible levels of essential oil ingestion when taken as part of the diet. A good example of this is oregano oil. Oregano oil is widely marketed for internal consumption, with numerous claims made about its therapeutic efficacy. In actual practice, the internal consumption of this oil frequently causes the typical symptoms associated with the ingestion of essential oils, such as extreme gastric hyperacidity. On the other hand, the use of oregano as a fresh herb, steamed at the end of food preparation, provides all the benefits of oregano oil at a biocompatible level, with none of the gastric dangers.
Should accidental ingestion of any significant amount of an essential oil occur, immediately call your local Poison Control Center. Do not induce vomiting. Do not give water if breathing or swallowing is difficult.
Do not apply directly to skin; always dilute with carrier oil.
Essential oils are very concentrated. Dilute all essential oils before applying to the skin, either in a fatty oil, or in water as when used on a compress.
There are two exceptions to this rule.
The first is the use of attars as natural perfumes. Because the floral essences are distilled into a base of sandalwood oil, the sandalwood oil acts as a carrier which dilutes the potency of the pure essential oil.
The second is the reasonable use of mild essential oils that have a well documented history of safety. The best example of this is lavender; however, even lavender can be problematic for some people.
Skin reactivity is becoming more of a problem as synthetic aroma chemicals become more common adulterants in the essential oil industry. A general rule is to never apply more than one to two drops of undiluted oil to the skin. Patch testing is always advisable. For people with sensitive skin, always test a small area with a diluted oil before applying over a larger area. For general non-medical use, avoid essential oils with highly sensitive skin and with any instances of skin allergies, severe inflammation and dermatitis. Pure essential oils are much less dangerous than synthetic aroma chemicals.
Skin reactions are dependent on the type of oil, the concentration of the oil, and the condition of the skin. Old and oxidized oils are more prone to cause reactions, especially rashes.
Refrigerate fatty carrier oils to prevent rancidity. Essential oils generally have a shelf life of one to three years. Some get better with age, such as sandalwood oil, vetiver oil, and patchouli oil. The citrus oils are most prone to degradation, and should be used within one year. Skin reactions to essential oils can take three forms:
- Irritation: A small number of oils are strongly or severely irritant. These include horseradish, mustard, garlic, and onion (which are rarely used in aromatherapy practice). Some oils used in massage practice can be moderately irritant, such as cinnamon bark oil, clove, fennel, and verbena. These oils should be used cautiously or avoided in cases of skin sensitivity.
- Sensitization: Skin sensitization means an allergic skin reaction; this usually manifests as a rash. There are relatively few oils used in a typical massage practice that will produce sensitization under normal applications in a carrier oil. However, there are a number of reports on Pubmed of allergic reactions to essential oils. These include contact dermatitis, eczema, asthma, and pruritic erythematous eruptions. These cases were predominantly among those who used essential oils professionally for long periods of time, such as massage therapists and estheticians. The cases frequently involved exposure to numerous essential oils, and it is also likely that the quality of the oils was poor.
- Phototoxicity: Some essential oils can strongly increase sensitivity to sunlight when applied to the skin. This is especially dangerous when applied undiluted to the skin, but even low concentrations in a carrier oil can cause problems if followed by exposure to sun or tanning lamps.
Phototoxicity will be much stronger directly after application of the oil, and will gradually decrease over an eight to twelve hour period; if higher than normal concentrations are used it can be longer. Most of the phototoxic oils are also photocarcinogenic. The most common oils which cause phototoxicity are the citruses; bergamot oil is the most reactive. Some citruses are phototoxic if expressed, but not if distilled, such as lemon oil and lime oil. Other oils include marigold oil (tagetes), verbena, and angelica oil.
The best practice is to use proper dilutions, avoid direct exposure to UV rays after application, and avoid the use of citrus oils if exposure will be occurring after treatment.
The best treatment for skin irritation from essential oils is to apply a fatty oil, such as coconut, which will dilute the impact of the essential oils. Avoid contact with eyes and mucous membranes. If an essential oil gets into the eye, do not rub it. Saturate a cotton ball with milk or vegetable oil and wipe over the area affected. In severe instances flood the eye area with lukewarm water for fifteen minutes.