Essential Oil Contraindications Quick Guide: Safety Reference for Practitioners

This quick-reference guide helps identify when specific essential oils should be avoided or used with caution. Use this as a starting point for safety assessment, then research specific situations thoroughly.

By Health Condition

Epilepsy / Seizure Disorders

Avoid completely:

Rosemary (all chemotypes)
Sage (Salvia officinalis)
Hyssop
Camphor
Fennel (sweet and bitter)
Spike lavender (Lavandula latifolia)

Use with caution:

Eucalyptus (especially globulus)
Peppermint (in large amounts)
Any oil high in camphor or thujone

Safer alternatives:

True lavender (Lavandula angustifolia)
Roman chamomile
Mandarin
Sandalwood

High Blood Pressure (Hypertension)

Use with caution:

Rosemary (stimulating effect)
Thyme
Hyssop
Sage
Peppermint (in excess)

Potentially helpful (not treatment):

Lavender (calming)
Ylang ylang (research support)
Marjoram
Clary sage

Note: Aromatherapy doesn't replace blood pressure medication. Any oil affecting stress/relaxation may have indirect effects.

Low Blood Pressure (Hypotension)

Use with caution:

Lavender (large amounts)
Ylang ylang
Marjoram
Clary sage

Potentially stimulating:

Rosemary
Peppermint
Black pepper

Diabetes

Use with caution (may affect blood sugar):

Cinnamon (all types)
Geranium
Dill
Fennel
Lemongrass

Important: Monitor blood sugar closely if using these oils regularly. Don't replace diabetes medication.

Kidney Disease

Avoid:

Juniper berry (all species)
Birch
Wintergreen

Use with caution:

Any oil at high concentrations (metabolism affected)

Liver Disease

Avoid:

Anise
Fennel
Basil (estragole-containing types)
High-phenol oils at high concentrations

Use with caution:

All oils metabolized by liver (most)
Lower dilutions recommended

Asthma / Respiratory Conditions

Use with caution (may trigger):

Eucalyptus (some individuals)
Peppermint (some individuals)
Strong aromatics (any)
Steam inhalation (can trigger)

Often helpful but individual:

Lavender
Frankincense
Roman chamomile

Note: Respiratory response to aromatics is highly individual. Introduce any oil slowly and monitor reaction.

Hormone-Sensitive Conditions

Including estrogen-dependent cancers, endometriosis, fibroids, breast cancer history

Avoid or use with caution:

Fennel
Anise
Clary sage
Sage
Geranium
Lavender (debated—research ongoing)
Tea tree (debated—research ongoing)
Cypress
Vitex

Note: The extent of estrogenic activity in these oils is debated in research. Conservative approach is avoidance; discuss with oncologist/healthcare provider.

By Medication Interaction

Blood Thinners (Anticoagulants)

Warfarin, heparin, aspirin therapy, Plavix, Eliquis, etc.

Avoid or use with extreme caution:

Wintergreen
Birch
Clove
Cinnamon (bark especially)
Ginger (high doses)
Garlic
Oregano

Why: These oils may enhance anticoagulant effects or contain coumarin derivatives.

Diabetes Medications

Use with caution:

Cinnamon (may enhance medication effect)
Fennel
Geranium
Dill

Why: May affect blood sugar levels; monitor and adjust medication with physician.

Blood Pressure Medications

Use with caution:

Rosemary (may counteract antihypertensives)
Sage
Thyme
Ylang ylang (may enhance hypotensives)

Why: May have additive or counteracting effects.

MAOIs (Antidepressants)

Avoid:

Nutmeg

Use with caution:

Any stimulating oils

SSRIs / Antidepressants

Use with caution:

Ylang ylang
Clary sage
Lavender
Bergamot

Note: Generally safer than with MAOIs, but monitor for enhanced sedation.

Antibiotics

May enhance or interfere:

Tea tree
Oregano
Thyme
Eucalyptus

Note: Some evidence of synergy; also potential interference. Professional guidance recommended.

Cytochrome P450 Affected Drugs

Many medications metabolized by CYP450 enzymes

Oils affecting CYP450:

Peppermint
Eucalyptus
Grapefruit (not the essential oil as much as juice)

Note: Potential for altered drug metabolism with significant topical exposure or ingestion.

By Population

Pregnancy

First Trimester (Avoid Most Oils)

Avoid completely:

Clary sage (uterine stimulant)
Jasmine (uterine stimulant)
Rosemary (high doses)
Sage
Thyme
Oregano
Cinnamon bark
Clove
Juniper berry
Pennyroyal (highly toxic)
Mugwort
Parsley seed
Tansy
Wormwood

Second/Third Trimester (Use Cautiously)

Generally considered safer at low dilution:

Lavender
Roman chamomile
Mandarin
Sweet orange
Grapefruit
Bergamot (FCF)
Sandalwood
Frankincense

Maximum dilution: 1% or less

Still avoid:

All first trimester avoidance oils
Peppermint (may affect milk supply if used near delivery)

Nursing/Breastfeeding

Avoid near breast/baby contact:

Peppermint (may reduce milk supply)
Sage (may reduce milk supply)
Menthol-containing oils

Avoid completely:

Same as pregnancy avoidance list

Safe with caution:

Lavender (away from breast)
Chamomile (away from breast)
Citrus oils (watch phototoxicity)

Infants (0-3 months)

Avoid topical use of most essential oils

If using (sparingly):

Lavender (minute amounts, highly diluted)
Roman chamomile (minute amounts, highly diluted)
Maximum 0.1-0.25% dilution

Avoid completely:

Eucalyptus (all types)
Peppermint
Rosemary
Any camphor-containing oil

Children (3 months - 2 years)

Avoid:

Eucalyptus globulus
Peppermint
Rosemary
Wintergreen/birch
Any high-cineole or menthol oil

Safe options (low dilution 0.25-0.5%):

Lavender
Roman chamomile
Mandarin
Sweet orange
Chamomile (German or Roman)

Children (2-6 years)

Avoid:

Peppermint near face
Eucalyptus globulus
Wintergreen
Birch

Safe options (0.5-1% dilution):

Lavender
Tea tree (diluted)
Eucalyptus radiata (gentler)
Citrus oils
Roman chamomile

Children (6-12 years)

Use with caution:

Peppermint (not near face)
Eucalyptus (radiata preferred)

Generally safe at 1-2%:

Most gentle oils
Adult oils at half concentration

Elderly

Considerations:

Thinner skin (lower dilutions)
Medication interactions (check all)
Slower metabolism
Sensitivity may be higher
Start at 0.5-1% dilution

By Oil Category

Phenol-Rich Oils

Oregano, thyme (thymol), clove, cinnamon

Contraindications:

Liver disease
Blood thinners
Children under 10
Pregnancy
Sensitive skin
Mucous membrane application

Maximum dilution: 0.5-1% (some lower)

Aldehyde-Rich Oils

Lemongrass, citronella, melissa, cinnamon bark

Contraindications:

Sensitive skin
Glaucoma (lemongrass)
Children (low dilution)

Maximum dilution: 0.5-1%

Ketone-Rich Oils

Sage, hyssop, pennyroyal, mugwort

Contraindications:

Epilepsy
Pregnancy
Children
Elderly (higher risk)
Neurotoxicity concerns

Some should be avoided entirely by non-professionals

Oxide-Rich Oils (High 1,8-Cineole)

Eucalyptus globulus, rosemary ct. cineole, bay laurel

Contraindications:

Children under 6-10
Near infant faces
Asthma (some individuals)

Maximum dilution varies by oil and population

Phototoxic Oils Reference

These oils can cause severe burns with UV exposure

Oil	Max % for UV Exposure	Risk Level
Bergamot (expressed)	0.4%	HIGH
Lime (expressed)	0.7%	HIGH
Bitter orange (expressed)	1.25%	Moderate
Lemon (expressed)	2%	Moderate
Grapefruit (expressed)	4%	Low
Cumin	0.4%	HIGH
Rue	Avoid	EXTREME
Angelica root	0.8%	HIGH
Fig leaf absolute	0.1%	EXTREME

Non-phototoxic citrus:

Steam-distilled versions
Bergamot FCF (bergapten-free)
Sweet orange
Mandarin (minimal)
Tangerine

Timeframe: Avoid UV exposure for 12-18 hours after application of phototoxic oils.

Skin Sensitizers

These oils may cause sensitization with repeated use

High sensitization risk:

Cinnamon bark
Peru balsam
Ylang ylang (with overuse)
Lavender (rare, with overuse)
Tea tree (oxidized)
Citrus oils (oxidized)
Jasmine absolute

Prevention:

Proper dilution
Rotation (don't use same oil daily indefinitely)
Fresh oils (replace oxidized oils)
Patch testing

Surgery Considerations

Pre-Surgery (Stop 7-14 days before)

Stop using:

Wintergreen
Birch
Clove
Garlic
Ginger (high doses)
Frankincense
Any oil affecting blood clotting

Post-Surgery

Avoid until cleared:

Blood-thinning oils (as above)
Strong stimulants

May be helpful (with approval):

Lavender (calming)
Peppermint (nausea)
Tea tree (wound care—diluted)

Quick Decision Tree

Before using any essential oil, ask:

Is the person pregnant or nursing? → Check pregnancy avoidance list
Is the person under 12? → Check age-appropriate limits
Are they taking medications? → Check drug interaction section
Do they have epilepsy? → Avoid proconvulsant oils
Do they have hormone-sensitive conditions? → Avoid potentially estrogenic oils
Will skin be exposed to sun? → Check phototoxicity limits
Any history of sensitization? → Extra caution; patch test

When in doubt, don't use. Consult professional resources or qualified practitioners.

Frequently Asked Questions

What if my client is on multiple medications? Check each medication. When multiple interactions are possible, consult with client's physician. Consider gentler oils or reduce concentration significantly.

Can I use oils around someone with allergies? Plant allergies don't always translate to essential oil reactions (different compounds), but proceed cautiously. Avoid oils from related plants. Patch test always.

What if an oil isn't listed here? This guide covers common oils and conditions. For unlisted oils, research their specific chemistry and associated cautions. When uncertain, avoid.

How do I know if sensitization has occurred? Repeated reactions to the same oil (redness, itching, rash) that worsen over time suggest sensitization. Once sensitized, avoid that oil permanently.

Should I stop all oils before surgery? Discuss with surgeon. Generally, stopping blood-affecting oils 7-14 days pre-surgery is prudent. Some surgeons prefer all supplementation stopped.

Are hydrosols safer than essential oils? Generally yes—hydrosols contain less concentrated compounds. However, some contraindications may still apply. Research specific hydrosols.

Last updated: December 2025. Safety information evolves with research. Verify current data for specific situations. This reference supplements professional training and individual assessment.