Learn more about the main chemical families present in essential oils: aldehydes, esters, ethers, ketones, monoterpenes, oxides, phenols, sesquiterpenols and more...

Understanding the basic chemical families of essential oils helps us better understand their therapeutic properties and safe use. While it's not always possible to assign identical effects to all members of a given family, knowing their general characteristics can provide valuable guidance when choosing the right oil.

We also recommend that you thoroughly familiarize yourself with the chemical composition of each oil (available in the GC/MS reports on our website) and its uses, benefits and safety guidelines.

Aldehydes

Therapeutic properties:

• Strong antifungal effect – recommended for combination with soothing oils, e.g. sandalwood or lavender.
• Anti-inflammatory and antispasmodic.
• Antibacterial and tonic for the nervous system.
• Cooling effect.
  

Safety rules:

• Oils rich in aldehydes can irritate the skin, especially after oxidation.
• Citral (geranial and neral) may be irritating to skin and mucous membranes.
• Use in low concentrations: 5-6 drops per 30 ml of carrier oil.
• Store oils with a high aldehyde content in tightly closed bottles in a dark and cool place.
• People with hormone-dependent cancers should avoid long-term use.

Examples of oils rich in aldehydes:

• Java citronella oil ( Cymbopogon winterianus )
• Lemongrass oil ( Cymbopogon flexuosus )
• Lemon balm oil ( Melissa officinalis )

Esters

Therapeutic properties

• Antispasmodic – ranging from mild to strong. Many aromatherapists consider isobutylangelate (found in Roman chamomile) to be one of the best antispasmodic ingredients.
• Calming, balancing, and soothing—regulating the autonomic nervous system. Oils rich in esters often have uplifting properties and are known as "balancing components."
• Analgesics (e.g. Roman chamomile, lavender, ylang-ylang).
• Digestive Support – Some esters are helpful in digestion, such as those found in cardamom, Roman chamomile, and bergamot oils.
• Anti-inflammatory – soothes skin irritations and rashes.
• Adaptogenic – support stress management.
  

Precautions

• Usually safe for skin.
• Exception: methylsalicylate (e.g. in wintergreen) may cause irritation.

Popular essential oils rich in esters

• Bergamot essential oil ( Citrus bergamia )
• Cardamom essential oil ( Elettaria cardamomum )
• Clary sage essential oil ( Salvia sclarea )
• Jasmine essential oil ( Jasminum sambac )
• Lavender essential oil ( Lavandula angustifolia )
• Roman chamomile essential oil ( Chamaemelum nobile )
• Rose and geranium essential oil ( Rosa x damascena / Pelargonium x asperum )
• Wintergreen ( Gaultheria fragrantissima ) essential oil

Ethers

Therapeutic properties:

• Antispasmodic action
• Supporting digestive health.

Precautions:

• They may irritate the skin.
• Use at higher doses may raise toxicity concerns – Recommended use at low concentrations (<1%) and only for emergency, short-term applications.
• Avoid during pregnancy and long-term use.

Examples of essential oils with a high ether content:

• Anise essential oil (Pimpinella anisum)
• Fennel essential oil (Foeniculum vulgare)

Ketones

Therapeutic properties:

• Mucolytic, expectorant, analgesic action.
• Some oils rich in ketones may support the healing of scars and wounds, such as lavender and vetiver.
• Peppermint, rosemary, camphor, and lavender may affect circulation.

Precautions:

• Ketones are different – they do not have identical therapeutic properties or the same safety restrictions, so each ingredient should be considered individually.
• Non-toxic ketones include menthone, verbenone, vetivone, fenchone, carvone, piperitone, jasmone, and tumerone.
• Some oils containing camphor (e.g., rosemary, camphor, lavender) may raise safety concerns.
• Camphor oils should not be used by people suffering from epilepsy, pregnant women, or people with high fever.
• Camphor-containing preparations should not be applied near the noses of infants and young children. Camphor ingestion by children can be fatal – just four teaspoons constitutes a lethal dose!
• Camphor can cause convulsions both when taken orally and, less frequently, when inhaled.
• Camphor can cause miscarriage, though only in near-lethal doses.
• Oils containing camphor should only be used for short periods and in small amounts.
• As a general rule, ketones should constitute a maximum of 1% in 30 ml of an essential oil blend.
• Ketones are more difficult to metabolize by the liver and can accumulate, raising concerns about long-term use at high doses. People with liver disease should use minimal amounts of ketone-rich oils.
• Camphor is a stimulant of the central nervous system (CNS), but in excess it can lead to CNS depression.

Examples of essential oils high in ketones:

• Peppermint essential oil (Mentha x piperita)
• Rosemary essential oil ct camphor (Rosmarinus officinalis ct camphor)
• Lavender essential oil (Lavandula latifolia)
• Turmeric essential oil (Curcuma longa)
• Vetiver essential oil (Vetiveria zizanoides)