The following information is adapted from the authoritative Salvatore Battaglia (2003). The Complete Guide to Aromatherapy. Brisbane: The International Centre of Holistic Aromatherapy.  

Atlas Cedarwood (Cedrus atlantica)

This essential oil is distilled from wood chips from the Atlas Cedar tree, and is used for stress, anxiety and tension, in addition to treating coughs and bronchial infections. It is also recommended for the treatment of skin and scalp conditions such as dandruff and acne. As an aromatherapy oil it has a strengthening and comforting effect, creating balance. 

Calendula (Calendula officinalis)

Calendula-infused oil has been traditionally used to treat skin conditions, varicose veins, and assist in the healing of wounds. Native to the Mediterranean, Calendula has antibacterial and anti-inflammatory properties which are extremely useful for treating minor burns (including sunburn), insect bites, eczema, and for promoting blood supply to body tissue.

Chamomile (Matricaria recutita)

Commonly used as a soothing tea to aid digestion and for its calming sedative effect, German Chamomile is also especially useful in the treatment of dry or itchy skin conditions such as eczema. As one of the gentlest essential oils, it is highly beneficial for treating children. With anti-inflammatory properties, Chamomile is effective in the treatment of muscular aches and pains, sprains, and inflamed and painful joints. Applied topically in massage or rubbed into the skin, Chamomile is known to promote relaxation, alleviates insomnia and can even assist with headaches. 

Eucalyptus (Eucalyptus radiata)

Eucalyptus oil is probably one of the most commonly known (and used) essential oils, with a history dating back to the mid-1800s, when Eucalytus radiata (Narrow-leaf Peppermint) was first distilled by Joseph Bosisto in Melbourne. Its most common uses are as an antiseptic and a decongestant/expectorant, both of which are excellent in the treatment and control of colds and congestion. It is also effective in treating headaches, muscular aches and pains and rheumatic discomfort. It can be applied directly (in carrier oil) such as in massage, or used as an inhalation such as in a bath or a vaporiser. Eucalyptus has also been found to improve mood and revive the spirits.

Lavender (Lavandula angustifolia)

Lavender has long been used in massage and as a vaporised essential oil to promote relaxation and relieve nervous tension and anxiety. Used to relieve rheumatic, sciatic, arthritic and menstrual pain, Lavender is also useful in the treatment of headaches and migraines, insomnia and to uplift the spirits of those feeling stressed or depressed.

Lavender can act both as an insect repellent, and to soothe insect bites. With antibacterial qualities, it is also useful for sunburn and skin conditions such as eczema, psoriasis, dermatitis and minor wounds. 

Mandarin (Citrus reticulata)

Mandarin oil is considered to aid digestion and relieve stomach upsets, especially in babies and children. It is a soothing oil, useful for combating restlessness and improving mood.

Myrrh (Commiphora myrrha)

Myrrh is extracted from the resin of the myrrh bush, and is one of the oldest known aromatic substances, dating back at least 4000 years. Reputed to promote youthfulness, it was used by Egyptian women in facial preparations to preserve the complexion. 

Now commonly used in the treatment of bronchial conditions, Myrrh is an expectorant, with astringent and antimicrobial properties. It is also considered useful in treating the nervous system, helping to alleviate stress and worry and promote inner calm.

Peppermint & Menthol (Mentha piperita)

Peppermint is a very commonly used oil, sought after for its medicinal properties for many centuries. With a cooling effect on mucous membranes, peppermint is particularly effective as a decongestant and to fight inflammation and infection. 

Applied topically as a liniment, peppermint is useful for treating muscular pain, lumbago and insect bites, with a local anaesthetic effect which helps to relieve skin irritation and itching.

Peppermint taken internally, such as in a tea, is highly effective in treating digestive complaints, relieving nausea and vomiting, stomach pains, diarrhoea and even travel sickness. It acts on the lymphatic system to stimulate blood flow and regeneration.

Additionally peppermint oil assists with concentration and mental fatigue, stimulating circulation, calming the nerves and relieving tension headaches and migraines.

Tangerine (Citrus reticulata blanco var. 'tangerine') 

Very similar to the Mandarin, Tangerine oil is cold-pressed from the peel of the fruit, and is used as a pleasant citrus flavouring. It has a sedative effect and can be effective in aiding and calming digestion, and can also be very useful in the treatment of acne.

Tea-tree (Melaleuca alternifolia)

Another Australian plant, tea-tree was used by Australian aborigines to relieve headaches long before European settlement. The name tea-tree came about in 1777 when Captain Cook used the leaves to make a tea to prevent scurvy. Distillation came much later in the 1920s, when the many properties of this oil were discovered. The oil acts as an antimicrobial against bacteria, viruses and fungi, and acts as an immunostimulant when the body is threatened with infection. It is recommended for people suffering from glandular fever or other illnesses to assist recovery and build the immune system. Most commonly, it is used for its antibacterial and decongestant properties, similar to eucalyptus oil and is very useful for those suffering from bronchial, asthmatic or other respiratory complaints. 

Tea-tree is also recommended for treating skin complaints such as acne, fungal infections, cold sores, dandruff, blisters, burns and cuts. It is one of few essential oils which can safely be used without a carrier oil. It helps to eliminate harmful pathogens and prevent recurrent infections.