A leading neurologist wants warnings on camphor and eucalyptus-based products which can lead to epileptic seizures - including over-the-counter essential oils and popular cold remedy Vicks.

Professor Gareth Parry has just returned from six months in India, where he said he had treated "at least one person each week" who had suffered an epileptic seizure caused by essential oils eucalyptus and camphor-based products.

The Wellington professor, who is an Officer of the New Zealand Order of Merit for services to neurology, said the link was under-reported and called for more research and reporting of the potential danger of the products for people with epilepsy.

"Essential oil use is common in India and not a week went by where I didn't treat someone who was stable on their medication and then had a seizure after using eucalyptus oil or Vicks VapoRub.

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"In New Zealand not many people are aware of the link and we need a careful public awareness campaign and labelling about this."

Professor Gareth Parry treated at least one person a week who had an epileptic seizure induced by eucalyptus oil. Photo / supplied
Professor Gareth Parry treated at least one person a week who had an epileptic seizure induced by eucalyptus oil. Photo / supplied

Parry was speaking out in response to news that an Auckland primary school stopped using diffused oils in 20 classrooms after a parent threatened High Court action.

Auckland lawyer Tim Rainey, threatened legal action against his son's school, Milford Primary on Auckland's North Shore, which started using diffusers and essential oils in class last month.

Rainey said the oils were triggers for his asthmatic son.

The electric diffusers - supplied to the school through multi-level marketing company dōTERRA - work by dispersing a mist of water and essential oil molecules throughout the room.

Parry supported Rainey's claim and said there was little risk for children without the conditions but it was significant for an epileptic or asthmatic child.

Since then, Parry has contacted MedSafe and spoken to the head of Epilepsy NZ about the link.

Parry shared the research from his colleague in Bangalore, India, Dr Thomas Mathew.

The head of neurology at St John's Medical College Hospital documented 10 cases of eucalyptus inhalation–induced seizures over the past two years in three tertiary-care hospitals.

Mathew aimed to raise awareness of seizures induced by exposure to eucalyptus oil in India and Professor Parry wants to do the same here.

Parry was working with Epilepsy NZ chief executive Graeme Ambler to highlight the risk some essential oils posed for people with epilepsy.

He also wanted "full disclosure" from companies about the risks some of their products have for certain users.

Eucalyptus essential oil can cause seizures in people with epilepsy. Photo / NZHerald.
Eucalyptus essential oil can cause seizures in people with epilepsy. Photo / NZHerald.

"I want to see labels on products with these essential oils in them just like you would for products containing nuts or that are unsafe to use during pregnancy," he said.

"It's a couple of lines on a jar and could save a life."

Parry also wanted doctors treating people after seizures to record if there had been recent exposure to convulsant products such as eucalyptus oil, camphor or rosemary oil.

In a statement a spokeswoman for Vicks, which produces popular cold remedies that can be applied topically or inhaled, said it understood there were reports of "certain ingredients found in Vicks products triggering alleged seizure attacks."

"Safety is a commitment on which we make no compromises - and which is the condition for trust with our consumers," the statement said.

The statement said the reports were "not established against Vicks products when used in accordance with the usage instructions."

The company said it was certain "consumers can continue to benefit from Vicks VapoRub safely when used as directed."

Parry said he would present Thomas's research, and his own findings at a meeting of New Zealand neurologists this month.