Aromatherapy carries several risks of
adverse effects; combined with the lack of evidence of its therapeutic benefit, the practice is of questionable worth.
Skin irritation and sensitisation Many studies have explored the concerns that essential oils are highly concentrated and can irritate the skin when used in undiluted form, often referred to as neat application. Therefore, they are normally diluted with a carrier oil for topical application such as
jojoba oil,
olive oil,
sweet almond oil or
coconut oil.
Phototoxic reactions may occur with many cold-pressed
citrus peel oils such as lemon or
lime. Many essential oils have chemical components that are
sensitisers (meaning that they will, after several uses, cause reactions on the skin and more so in the rest of the body). Some oils can be toxic to some domestic animals, with cats being particularly prone. Most oils can be toxic to humans as well.
Endocrine-disrupting effects A report on three different cases documented
gynecomastia in prepubertal boys who were exposed to topical lavender and
tea tree oils. The Aromatherapy Trade Council of the UK issued a rebuttal. Another article published by a different research group also documented three cases of
gynecomastia in prepubertal boys who were exposed to topical lavender oil. Persistent exposure to lavender products may be associated with premature breast development in girls and "that chemicals in lavender oil and
tea tree oil are potential
endocrine disruptors with varying effects on receptors for two hormones –
estrogen and
androgen".
Poisoning Essential oils can be toxic when ingested or absorbed internally. Doses as low as 2 ml have been reported to cause clinically significant symptoms and severe poisoning can occur after ingestion of as little as 4 ml. A few reported cases of toxic reactions like
liver damage and seizures have occurred after ingestion of sage, hyssop, thuja and cedar oils. Accidental ingestion may happen when oils are not kept out of reach of children. As with any
bioactive substance, an essential oil that may be safe for the general public could still pose hazards for
pregnant and
lactating people. Oils both ingested and applied to the skin can potentially have negative interactions with conventional medicine. For example, the topical use of
methyl salicylate-heavy oils like
wintergreen may cause bleeding in users taking the
anticoagulant warfarin.
Bacterial contamination In late 2021, an aromatherapy spray was recalled after it was found to be contaminated with
Burkholderia pseudomallei, the bacterial agent that causes
melioidosis, which led to four cases of the disease and two deaths. ==See also==