Presenter Information

Cecile Bascoul, doTerraFollow

Document Type

Oral Presentation

Location

Oxford Convention Center, 102 Ed Perry Boulevard Oxford, MS 38655

Event Website

https://www.oxfordicsb.org/

Start Date

27-4-2023 11:30 AM

Description

Eucalyptus essential oil (EO) and preparations containing eucalyptus EO have been used in traditional medicine for centuries for the treatment of respiratory illnesses such as cold, influenza and sinus congestion. Research, including clinical trials, has been carried out to evaluate the efficacy of eucalyptus alleviating symptoms of such conditions. However, eucalyptus EO and preparations with eucalyptus EO have also been associated with rare cases of CNS depression and seizures. The case reports reviewed showed evidence of CNS depression and/or seizure in patients from all ages (<1 to 74 year-old) with different doses of eucalyptus EO (0.18 mL to 1000 mL). Most of the adverse events were in children; some of them reacting to small doses (4 drops of EO or about 0.24 mL), ingested, inhaled or after topical application. Most children who developed seizures did not have a history of seizures before the event. The main constituent of eucalyptus EO is 1,8-cineole (about 65% to 84% 1,8 cineole for eucalyptus globulus EO, one of the most commonly used eucalyptus species in commercially available products). Camphor is also often present in preparations used to alleviate respiratory symptoms.

A literature review was done to better understand the CNS effects of eucalyptus EO, 1,8-cineole, and camphor. Contradictory information of whether eucalyptus EO, 1,8-cineole, or camphor induce seizures was found. In 2014, Tisserand reported that seizures represented only 2% of adverse events related to eucalyptus EO, however, 1,8-cineole was not believed to be the cause due to its CNS depressant effect. Other case reports as well as in vitro and in vivo research showed a different outcome, with seizures being reported in human adults exposed to eucalyptus EO, and animals exposed to 1,8-cineole. In vivo and in vitro research also point to an increased risk of seizures after exposure to camphor. We did not find information about the chirality of camphor and how it impacts its effects in the CNS response, although no adverse events related to CNS response or seizures were found for blue tansy EO which contains L-(-)-camphor.

The goal of this research is to expand our knowledge of eucalyptus EO, its main constituent 1,8-cineole, and camphor, along with other essential oils containing these compounds to better understand potential side effects, improve usage indications, and evaluate the necessity of potential warnings on product labels. One cannot exclude other factors such as potential adulteration or contamination of the essential oils incriminated in case reports. Further investigations are warranted to determine the composition of the specific products used by patients experiencing the seizures. More research is needed to evaluate the data and understand the case reports.

Publication Date

April 2023

Accessibility Status

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Apr 27th, 11:30 AM

Eucalyptus essential oil: a safety assessment and causality evaluation of published case reports

Oxford Convention Center, 102 Ed Perry Boulevard Oxford, MS 38655

Eucalyptus essential oil (EO) and preparations containing eucalyptus EO have been used in traditional medicine for centuries for the treatment of respiratory illnesses such as cold, influenza and sinus congestion. Research, including clinical trials, has been carried out to evaluate the efficacy of eucalyptus alleviating symptoms of such conditions. However, eucalyptus EO and preparations with eucalyptus EO have also been associated with rare cases of CNS depression and seizures. The case reports reviewed showed evidence of CNS depression and/or seizure in patients from all ages (<1 to 74>year-old) with different doses of eucalyptus EO (0.18 mL to 1000 mL). Most of the adverse events were in children; some of them reacting to small doses (4 drops of EO or about 0.24 mL), ingested, inhaled or after topical application. Most children who developed seizures did not have a history of seizures before the event. The main constituent of eucalyptus EO is 1,8-cineole (about 65% to 84% 1,8 cineole for eucalyptus globulus EO, one of the most commonly used eucalyptus species in commercially available products). Camphor is also often present in preparations used to alleviate respiratory symptoms.

A literature review was done to better understand the CNS effects of eucalyptus EO, 1,8-cineole, and camphor. Contradictory information of whether eucalyptus EO, 1,8-cineole, or camphor induce seizures was found. In 2014, Tisserand reported that seizures represented only 2% of adverse events related to eucalyptus EO, however, 1,8-cineole was not believed to be the cause due to its CNS depressant effect. Other case reports as well as in vitro and in vivo research showed a different outcome, with seizures being reported in human adults exposed to eucalyptus EO, and animals exposed to 1,8-cineole. In vivo and in vitro research also point to an increased risk of seizures after exposure to camphor. We did not find information about the chirality of camphor and how it impacts its effects in the CNS response, although no adverse events related to CNS response or seizures were found for blue tansy EO which contains L-(-)-camphor.

The goal of this research is to expand our knowledge of eucalyptus EO, its main constituent 1,8-cineole, and camphor, along with other essential oils containing these compounds to better understand potential side effects, improve usage indications, and evaluate the necessity of potential warnings on product labels. One cannot exclude other factors such as potential adulteration or contamination of the essential oils incriminated in case reports. Further investigations are warranted to determine the composition of the specific products used by patients experiencing the seizures. More research is needed to evaluate the data and understand the case reports.

https://egrove.olemiss.edu/icsb/2023_ICSB/schedule/13