Oils, which generally should not be used in aromatherapy.

These oils are considered too dangerous to be able to use them in aromatherapy. All of them, or drugs, or poisons that can provoke, seizure or serious damage to the skin. Some of them may lead directly to a range of adverse effects. So, the most dangerous list:

 - Bitter Almonds (Primus amygdalis, var. Amara)
 - Arnica (Arnica montana)
 - Bald (Peumus boldus)
 - Air cane (Acorus Calamus)
 - Camphor (Cinnamomum camphora)
 - Cassia (Cinnamomum cassia)
 - Kostusev (Saussurea lappa)
 - Elecampane (Inula helenium)
 - Fennel (Foeniculum vulgare)
 - Horseradish (Cochlearia armorica)
 - Mugwort (Artemisia vulgaris)
 - Mustard (Brassica nigra)
 - Oregano (Origanum vulgare)
 - Pennyroyal (Mentha pulegium)
 - Stone pine (Pinus pumilio)
 - Rue (Ruta graveolens)
 - Sage (Salvia officinalis)
 - Cossack juniper (Juniperus sabina)
 - Summer savory (Satureia hortensis)
 - Winter savory (Satureia montana)
 - Tansy (Tanacetum vulgare)
 - Thuja occidentalis (Thuja occidentals)

Oils that should be used with caution:

There are many oils having valuable therapeutic properties, but can cause undesirable effects. Except for the oil of bergamot, completely safe as long as they treated skin is not exposed to sunlight, ordinary reader would be wise to avoid these oils, leaving the right to carry out medical procedures with their use of a qualified aromatherapist.

The following categories of people and sage oil
wormwood is better not to use.

Oils, is contraindicated in patients with epilepsy:
 - Fennel (Foeniculum vulgare)
 - Hyssop (Hyssopus officinalis)
 - Rosemary (Rosmarinus officinalis)

Oils and contraindicated in pregnancy:
 - Basil (Ocimum basilicum)
 - Birch (Betula alba, B. lenta, B. alleghaniensis)
 - Atlas cedar (Cedrus atlantica)
 - Clary Sage (Salvia sclarea)
 - Cypress (Cupressus sempervirens)
 - Geranium (Pelargonium asperum)
 - Jasmine (Jasminium officinale)
 - Cossack juniper (Juniperus sabina)
 - Marjoram (Origanum majorana)
 - Myrrh (Commiphora myrrha)
 - Nut nutmeg (Myristica fragrans)
 - Peppermint (Mentha piperata)
 - Rosemary (Rosmarinus officinalis)
 - Tarragon (Artemisia dranunculus)
 - Thyme (Thymus vulgaris)

Oils, which can be poisoned.
Use these oils with caution and within no more than a few days:
 - Basil (Ocimum basilicum)
 - Atlas cedar (Cedrus atlantica)
 - Eucalyptus (Eucalyptus globulus)
 - Fennel (Foeniculum vulgare)
 - Lemon (Citrus limonum)
 - Orange (Citrus aurantium)
 - Nut nutmeg (Myristica fragrans)
 - Thyme (Thymus vulgaris)
 - Oils and skin irritants

Always dilute these oils to 1% prior to use:
 - Citronella (Cymbopogon nardus)
 - Clove (Eugenia caryophyllus)
 - Lemon (Citrus limonum)
 - Orange (Citrus aurantium)
 - Nut nutmeg (Myristica fragrans)
 - Peppermint (Mentha piperata)

Oils, increase the photosensitivity of the skin.
Do not use these oils to the skin before going out in the sun:
 - Bergamot (Citrus beigamia)
 - Lemon (Citrus limonum)
 - Orange (Citrus aurantium)