Oil of Oregano Update

April 9, 2012 By

By Sorcha Kellett, BSc
Regulatory Scientific Affairs Assistant

Oil of Oregano (Origanum vulgare leaf extract) has been used traditionally for its health and medicinal benefits including improvement of immune function and respiratory health. Carvacrol is present as a major constituent in the essential oil of Origanum vulgare.

The effects of oregano oil have been investigated in several clinical trials. It has been shown to inhibit or decrease growth of several pathogenic bacteria (Force et al, 2000), and to have antioxidant properties (Faleiro et al, 2005).

Health Canada has recently changed the upper limit of carvacrol specified for Natural Health product formulations.

The Natural Health Products Directorate (NHPD) has confirmed a limit of 2.7 mg/kg body weight/day, which is equivalent to 189 mg for an average adult (70 kg). The previous limit of 0.23 micrograms/kg body weight/day has yet to be updated in the Natural Health Product Ingredient Database (NHPID).

Furthermore, the NHPID made the following recent alterations (March 2012):

Origanum Vulgare Leaf Oil previously described as having a medicinal and non-medicinal role is now described as only having a non-medicinal role. Oregano Oil has been added as a new ingredient having a medicinal role.

According to the Canadian Health Food Association (CHFA), based on product licence applications submitted to NHPD containing oil of oregano, the vast majority of products containing oil of oregano on the market, contain levels of carvacrol which are well under the above outlined threshold level. The NHPD has contacted the few companies that initially exceeded this limit and advised CHFA that any concerns have been resolved to date.

Dicentra will continue to bring you updates as more information becomes available.


Mark Force, William S. Sparks and Robert A. Ronzi, ‘Inhibition of Enteric Parasites by Emulsified Oil of Oregano in vivo’ Phytother. Res. 14, 213–214 (2000)

  1. Faleiro et al, ‘Antibacterial and Antioxidant Activities of Essential Oils Isolated from Thymbra capitata L. (Cav.) and Origanum vulgare L.’, J. Agric. Food Chem. 2005, 53, 8162-8168
  2. CHFA (2012) Available at: www.chfa.ca
  3. http://webprod.hc-sc.gc.ca/nhpid-bdipsn/search-rechercheReq.do [Accessed on April 2nd, 2012].

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