| ESSENTIAL OIL
SAFETY CONSIDERATIONS
The use of distilled essential oils goes back
some 1,000 years, and few hazardous incidents have occurred. Today
the greater application by doctors and therapists requires a substantial
knowledge of safety. Most of the research done on the safety of
essential oils is a by-product of scientific toxicity studies for
their inclusion in food, perfumes and toiletry products and therefore
a considerable amount of data is available. There are toxic essential
oils, but the majority are not and the hazards are well documented.
It has been shown that when properly diluted, essential oils are
relatively safe and compared to other things we ingest, the use
of essential oils in general seem to be fairly safe.
Employed as whole plants for thousands of years,
in the form of herbology, the active principle, essential oils,
are very much more concentrated than in the plant. The essential
oil within plant tissues capable of extraction varies but the yield
is often less than 1 % and distillation can concentrate this up
to 99 times. Therefore the properties become more important, especially
when used on the skin as well as in emotional treatments. Also,
one cannot assume that an essential oil will cause the same actions
as those attributed to the whole plant. Fresh and dried aromatic
plant material contains active compounds besides essential oils,
and these do not appear in the distilled oil. Some of the most potent,
medicinally active substances are water-soluble only, therefore
will not appear in the essential oil? only in distillate water or
tincture. Absolutes, concretes1 and CO2 (total) extracts do contain
some non-volatile constituents and this explains why they can be
more irritant than distilled or CO2 (selective) extracts.
Toxicity, irritation, and sensitization are the main
areas of interest with essential oil safety.
TOXICITY
Toxicity refers to poisoning, which can become fatal, whether dermal
(through skin), oral, or other methods, and is dose-dependent. A
less than lethal dose can also cause liver and kidney damage especially
when used over a long period of time. Toxicity is dose-dependent,
as follows: Acute toxicity occurs after a single dose or application
and chronic toxicity occurs over a period of time (weeks, months,
or years) or after repeated applications.
The most toxic essential oils (such as rue and wintergreen)
can cause convulsions in high doses and are known to have vermifuge
action (kills internal parasites). Some essential oils are toxic
to worms (wormseed); and the antibacterial action or at least the
amounts of essential oil required for toxicity to pathogenic bacteria
(as found in eucalyptus, cinnamon, and bergamot) is not related
to human toxicity at least in that amount. However, larger amounts
can have undesirable effects.
The vast majority of essential oils have low toxicity
when dompared to other potent, readily available medicines such
as aspirin. In most cases, an adult would have to drink a large
amount (cupful) of essential oil for death to occur and the over-the-
counter medications are far more toxic and damaging to the body
on a weight-for- weight basis, than most essential oils. Surveys
of worldwide literature on human toxicity over many years have only
uncovered a handful of deaths resulting from ingestion of essential
oils. A number of cases exist of stomach upsets from excess consumption
and in a few cases where severe illness resulted (including liver
function disorders) and recovery occurred, liver and other functions
have been totally restored unlike toxicity resulting from other
chemicals. Two types of toxicity, oral and dermal, are relevant
for aromatherapy studies.
Oral toxicity:
This occurs from a single dose, orally, and the toxic effect on
the body is viewed in terms of lethal dosage. Although toxicity
tests on animals (LD50) give an indication of likely human toxicity,
the results are inconsistent and can only be a guide. Even though
it would almost be impossible for someone to drink the amount needed,
it could result in death. The majority of essential oils taste so
bad a child would not be tempted, however aniseed is one that could
be quite tasty. There are a few essential oils in which only a few
milliliters (5-10 mlsi could result in death. For example, animal
tests of eucalyptus globulus indicate a probable lethal dose for
a child as being 34 mIs., yet the death of a child has occurred
after ingesting just 5 mIs. of eucalyptus. Some factors to consider
are the variability of essential oil chemical constituents, the
purity of product, along with the fact that some oils have had no
formal testing at all. In addition, consider the condition of individual
susceptibility to certain oils - patients with liver / kidney weakness
or other chronic illness may be more affected, since essential oil
toxicity damages those organs.
The following oils are considered very toxic
if taken orally:
boldo leaf horseradish mustard savin
These are considered harmful orally:
almond, bitter jaborandi mugwort santolina
sassafras (both) tansy (common) wormseed tonka bean wormwood
(common) thuja Moderately toxic orally: basils (methyl
chavicol type), bay (leaf), birch (sweet & birch tar
oil), cade (rectified), camphor (yellow & brown),
deertongue, elecampane root (I. helenium)*, common mugwort,
rue, turpentine (unrectified), wintergreen Possible toxicity,
caution orally: arnica, ajowan, boronia absolute, buchu,
cassia, cassie, costus root, hyssop, nutmeg, osmanthus,
parsley seed, savory (winter), tagetes, thyme
No Formal Toxicity Testing:
cassie, yarrows (ligurie, musk), calamus
(shyobunone), large galanga, galanga, ammi visnaga, amyris,
angelica root, chervil, celery plant, aloe wood, Ianyana,
annual wormwood, artemisia arborescens, white mugwort
(davanone, thujone types), davana, boronia, buplevre,
calamint, calendula, calophyllum, elemi, sweet hemp seed,
Himalayan cedarwood, ormenis, balsamita, Japanese camphor,
sugandha, cistus, bergamot petitgrain, combava (&
petitgrain), Persian lime, mandarin petitgrain, common
fleabane, sea samphire, massol, Arizona cypress, cypress
wood, Zeodoary turmeric, gingergrass, cyperus, carnation,
borneol camphor, eriocephalee, eucalyptus (camaldulensis,
campanulata, dives, polybracteas, austrailiana, smithii,
staiger,ana), Australian sandalwood, asafetida, Siam wood,
angostura, gardenia, zdravetz, guaiacum, hedychium, helichrysum
(gymnocephaljum), hernandia bark, hyssopdecumbens, inula,
alpine juniper, lantana, larch, laserwort, lavender stoechas,
hina, labrador tea, leptospermum, lovage, mammea, melaleuca
(narrow leaf, white, uncinata), niaouli (cineole, nerolidol),
melilotus, peppermint-piperitonetype, apple mint, champaca,
wild bergamot, sweet gale, green myrtle, spikenard, catnip,
nigella, basil (large green leaf, bush, camphor type,
eugenol, thymol), true opoponax root, Greek oregano, wild
oregano, osmanthus, kewda, parsnip, butterbur, sachaline
spruce, pine (Swiss stone, laricio, sea pine, longleaf),
mastic, pittosporum, Douglas fir, ravensara, ravensara
anisata, rhododendron, rosemary (cineole, verbenone, pyramidalis),
sage (Italian, Greek, decumbens), winter savory, schinus
molle, skimmia, goldenrod, meadowsweet, blue tansy, germander,
cat thyme, condo thyme, thyme (borneolcarvacrol, wild,
citral, geraniol, linalool, paracymene, thuyanol), linden,
ajowan (seed & plant), hemlock spruce, valerian (Japanese,
Indian), fagara, mulilam, Cassumar ginger
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