Essential Oil Safety

The essential oils below are potentially convulsant for anyone who might be vulnerable to epileptic seizures (Tisserand and Young p.134, table 10.2).

  • Western Red Cedar

  • Wormwood

  • Genipi

  • Hyssop (ct pinocamphone)

  • Sage

  • Thuja

  • Pennyroyal

  • Buchu

  • Calamint

  • Tansy (Tanacetum vulgare)

  • Mugwort, Lanyana

  • Ho Leaf (ct camphor)

  • Boldo

  • Wintergreen

  • Birch

  • Rosemary

  • Yarrow

  • Spanish Lavender (Lavandula stoechas)

  • Feverfew

  • Spike Lavender (Lavandula latifolia).

Robert Tisserand and Rodney Young’s book, Essential Oil Safety: A Guide for Health Care Professionals (second edition) provides the information below to help us understand the potential risks and safety conditions to consider for specific people and conditions.

Pregnancy & Breastfeeding
  • During pregnancy & breastfeeding typically it is recommended to keep your essential oil concentration at low level. Balancing Botanicals suggests 1%.

  • Balancing Botanicals advises pregnant & breastfeeding women to use essential oils under the guidance of an Aromatherapist or medical professional knowledgeable about essential oils.

TIsserand & Young (charts p. 152 - 153 & p. 156) indicate there are approximately 50 essential oils that are contraindicated during pregnancy, and another 15 that should be restricted during pregnancy and lactation. 

Commonly used oils contraindicated during pregnancy are:​

  • Anise

  • Birch

  • Black Seed

  • Carrot Seed

  • Cinnamon bark

  • Blue Cypress (Callitris intratropica)

  • Fennel

  • Ho leaf (Cinnamomum camphora ct. camphor)

  • Hyssop (Hyssopus officinalis ct. pinocamphone)

  • Myrrh

  • Spanish Lavender (Lavandula stoechas)

  • Oregano

  • Sage (Salvia officinalis, Salvia lavandulifolia)

  • Wintergreen

High Blood Pressure

Tisserand and Young indicate no evidence to support the contraindication of topical use of essential oils in reference to high blood pressure. (Tisserand and Young p. 658)

Phototoxic (Sun Sensitive)

Phototoxic oils are oils that can cause skin irritation similar to a sun burn when exposed to sun light.  


Tisserand and Young indicate (p.659) sunlight or tanning bed rays must be avoided for up to 18 hours after application if any of these oils are used. 

  • Bergamot

  • Bitter Orange

  • Cold pressed Lime

  • Cumin

  • Grapefruit

  • Laurel Leaf absolute

  • Lemon

  • Mandarin Leaf

  • Rue

  • Taget


Due to potential and unpredictable effects on the immune system, Robert Tisserand recommends that essential oils are avoided from one week before to one month following a course of chemotherapy or radiotherapy. (Tisserand and Young p. 656).


Using oils via inhalers to manage nausea and anxiety during chemotherapy or radiotherapy is an alternative suggested by other Aromatherapists.

Eyes & Ears

Essential oils should not be used in the eyes or ears.

Liver & Kidney Imparment

Intensive or over use of phototoxic oils are not recommended if there is significant hepatic (liver) and renal (kidney) impairment.

Drug Interactions

Always consult a physician if you are taking medications.  Many essential oils can cause adverse side effects when taking certain medications.  Medications of specific concern would be any heart medications, emotional support medications, and those used to sedate.  Interactions are not limited to these types of medications.  Please consult a physician when taking medications.

Blood Thinners

Wintergreen & Birch are known to inhibit blood coagulation and may increase the effects of any drugs intended to thing the blood. Even small topical application can cause adverse side effects and should be avoided by people with clotting disorders, major surgery, childbirth, peptic ulcer or hemophilia.

Aspirin Sensitivities

Wintergreen & Birch are converted into salicylic acid in the body, therefore should not be used for anyone with aspirin sensitivities.