The Sunlight Experiment

Compound Monograph

Camphor

Camphor — a sharp, penetrating, medicinal-smelling bicyclic monoterpene ketone found in yarrow and feverfew essential oils, useful in dilute aromatic preparations but genuinely toxic if ingested in quantity.

Work in progress

Classification

Camphor is a bicyclic monoterpene ketone, part of the terpenoids class. The largest class of plant compounds, built from five-carbon isoprene units — the essential-oil aromatics, resins, bitter principles, saponins, and plant sterols.

Terpenoids Monoterpenes

Where Does It Come From? (8)

Camphor is a naturally occurring bicyclic monoterpene ketone, found in Feverfew, Yarrow, Muira Puama and 5 other sources. It is flagged as moderately toxic.

Camphor laurel Chrysanthemum Chrysanthemum morifolium Feverfew Tanacetum parthenium Lavender Lavandula angustifolia Muira Puama Ptychopetalum olacoides Rosemary Rosmarinus officinalis Sage Yarrow Achillea millefolium

Research & Evidence

Camphor is a bicyclic monoterpene ketone with a sharp, penetrating, medicinal aroma familiar from chest rubs and liniments. In this database it appears as a component of a small number of aromatic essential oils:

  • Feverfew (Tanacetum parthenium) — camphor is reported as the single largest component of feverfew’s volatile oil, at roughly 56.9%, alongside camphene, p-cymene and bornyl acetate 1Reference 1Akpulat H et al. · 2005Composition of the essential oils of Tanacetum argyrophyllum (C.
  • Yarrow (Achillea millefolium) — camphor makes up around 17.79% of yarrow’s volatile oil, one of its more abundant terpenes 2Reference 2Battaglia · 2003The Complete Guide to Aromatherapy (2nd ed.).
  • It is also listed among the plant chemicals of muira puama (Ptychopetalum olacoides) and in the constituent list of rosemary (Rosmarinus officinalis).

The source monographs treat camphor as a characterising essential-oil constituent rather than crediting it with specific isolated activities, so this is kept short. The references below are the source-herb citations that genuinely pertain to camphor.

Toxicity & Safety

Unlike most of the gentler volatile-oil terpenes, camphor warrants real caution. It is readily absorbed and is genuinely toxic and neuroactive when taken internally in quantity: concentrated camphor or camphor-rich essential oils can cause nausea, vomiting, agitation and seizures if ingested, and this risk is greatest in infants and children. For this reason it should never be swallowed in concentrated form, and camphor-rich oils should be kept well diluted and used only externally and sparingly. The very small proportions of camphor present within whole herbs are a different matter from concentrated oil, but the compound itself is correctly regarded as more hazardous than terpenes such as limonene or linalool — which is why it is flagged here as moderately toxic. Camphor oil is also a recognised adulterant of other mint and essential-oil products, another reason to be sure of the source and quality of any aromatic preparation.

References

  1. Akpulat H, Tepe B, Sokmen A, Daferera D, Polissiou M. (2005). Composition of the essential oils of Tanacetum argyrophyllum (C. Koch) Tvzel. var. argyrophyllum and Tanacetum parthenium (L.) Schultz Bip. (Asteraceae) from Turkey. Biochem Syst Ecol. 33:511–6.
  2. Battaglia, S. (2003). The Complete Guide to Aromatherapy (2nd ed.). Brisbane, Australia: The International Centre of Holistic Aromatherapy. (Pg 276-277).