Rosemary CO2 vs essential oil is my topic for this week. Once again we find that there are similarities but as always there are also differences to know about.  Knowing these we are able to choose the best aromatic for the job at hand.

Common to both

Name: Rosemary (Rosmarinus officinalis)

Family: Lamiaceae (Labiatae) 

Description:  Rosemary is an evergreen perennial shrub with needle-like silver-green leaves and small, tubular, pale-blue flowers.  R. officanalis ct. cineole is a small bush with evergreen leaves and blueish or sometimes white flowers, while  R. officinalis ct. verbenone is a robust perennial bush that can grow to between 1 – 2 meters high.  Leaves are grey-green and needle-like and the flowers range from whitish to blue.  This plant likes a marine climate.

History/Folklore: The name comes from the Latin ‘ros marinus’ meaning ‘rose of the sea’.  In Ancient Egypt the springs were burnt as ritual incense and placed in the tombs of pharaohs.  To the Greeks and Romans, the plant was sacred, being symbolic of loyalty, scholarly learning, death and remembrance.  In flower lore, rosemary means remembrance, possibly due to its ability to improve memory.   During the sixteenth century hospitals burned rosemary to purify the air and prevent the spread of infection.  Sprigs were place on pillows to ward off demons and prevent bad dreams.


Method of Extraction

CO2 :  A CO2-select extract is obtained from the dried plant material Rosemary ct. cineole, using carbon dioxide as the ‘solvent’ to extract the viscous liquid.
Essential Oil:  The essential oil is steam distilled from the flowering tops.

Colour and Appearance

CO2:  CO2 select extract is transparent and yellow fluid. (Kerkhof)  CO2 extract is an olive-green brown plastic solid. (Burfield)
Essential Oil:
A colourless to pale yellow liquid.  (Burfield)


CO2:  Fresh, clear scent with a hint of eucalyptus. (Kerkhof)Rich herbaceous aromatic sweet odour with surprising depth.   (Burfield)
Essential Oil:
Fresh, sweet, camphor-like with differences in nuances depending on the chemotype.  (Burfield)


CO2:  The CO2-select extract ct. cineole consists of around 80 – 85% essential oil with around 40 – 45% Oxides (1,8 cineole), 15% Ketones (camphor); 20% Monoterpenes (a-pinene, camphene, limonene, p-cymene, myrcene, humulene); 13% Sesquiterpenes (b-caryophyllene); 5% Alcohols (a-terpineol, borneol). (Kerkhof)
Essential Oil:
  Rosemary ct. cineole consists of around 48% Oxides (1,8-cineole); 11% Ketones (camphor), 6% sesquiterpenes (b-caryophyllene); 27% monoterpenes (a-pinene, b-pinene, camphene, limonene, p-cymene and myrcene; 8% alcohols (terpineol, linalool, borneol, terpinen-4-ol). (Caddy)


 CO2: Can be highly stimulating.  Not suitable for hyperactive people, ADHD and in cases of unrest or agitation.  Avoid in people with a tendency to epilepsy or brain tumors.  For those who are prone to airway cramps or asthma one should avoid all cineole rich oils.  Rosemary CO2 should not be used during pregnancy or with infants and children under 6.  (Kerkhof)
Essential Oil:
Generally considered non-toxic, non-irritating and non-sensitizing.  As it is highly stimulating do not use when you need to sleep.  Use with caution with epilepsy, high blood pressure and pregnancy.
Rosemary ct. camphor might be neurotoxic (Tisserand and Young)

Indications for Use 

CO2:  On a physical level as a prevention and treatment of airway infections, rhinitis, bronchitis, sinusitis, flu and possibly anti-inflammatory in pleurisy; oily skin, acne, hair loss, promotion of hair growth; headaches, migraine; muscle and joint pains; digestive cramps.  (Kerkhof)
Essential Oil:
  On a physical level Asthma, bronchitis, whooping cough; colds, flu, infections; acne, dermatitis, eczema, lice, hair and scalp use;  gout, muscular pain, neuralgia, poor circulation, varicose veins, rheumatism; colitis, dyspepsia, flatulence, dysmenorrhea and leukorrhea.

Emotional and Spiritual Conditions

Both the CO2 extract and the essential oil have stimulating properties and are worth considering when there is physical exhaustion, feeling rundown, headaches, migraines, mental fatigue and nervous exhaustion. Rosemary is also excellent for memory. On a subtle level, Rosemary is used in blends for loyalty and love.   The energetics of this aromatic are said to comfort emotional heartbreak and may be appropriately used to help achieve closure to a relationship.  The long association of rosemary with death and remembering explains why it is so helpful in grief blends. In Dr. Berkowsky’s Spiritual PhytoEssencing, in addition to the themes of faithfulness and memory, Rosemary also has the theme of metamorphosis.  So when I am creating blends in which I want to include the theme of transition and change I will often add a little Rosemary.

You might also enjoy the articles in the Article Archives on Rosemary essential oil and Hair Care and the blog on Hair Loss.

An interesting study comparing Rosemary essential oil with minoxidil 2%. Showed that Rosemary essential oil was more effective and had fewer side effects in the treatment of androgenetic alopecia compared to minoxidil 2% a standard treatment for this condition.

Tony Burfield, Natural Aromatic Materials – Odours & Origins, 2000
Ernst Guenther, The Essential Oil, Vol I-V, 1948 reprinted 1972
Madeline Kerkhof, CO2 Extracts in Aromatherapy, 2018Leung and Foster, Encyclopedia of Common Natural Ingredients, 1996Tisserand and Young, 2nd Edition Essential Oil Safety, 2014