Of all the many forms of so-called alternative medicine (SCAM), essential oils (EOs) are perhaps the most popular and least harmful – at least this is what we are supposed to believe. The truth is, as so often in SCAM, a little different.
Some EOs are claimed to have anticonvulsant activity and might benefit people with epilepsy. Lemongrass, lavender, clove, dill, and other EOs containing constituents such as asarone, carvone, citral, eugenol, or linalool are good candidates for evaluation as antiepileptic drugs. Conversely, other EOs are suspected to have pro-convulsant properties. These EOs are present in many balms and oils available freely over the counter. The effect of exposure to these EOs and occurrence of seizure has not been studied systematically. The aim of this study was therefore to evaluate the relationship between essential oils and the first episode of seizure and breakthrough seizures in known epileptic patients.
This multi-center prospective study was conducted in four hospitals in India over four years. Every person presenting with the first episode of seizure or breakthrough seizure was asked about exposure to EOs, mode of exposure, time to onset of a seizure in relation to exposure, duration of seizure, type of seizure, and antiepileptic drug therapy.
During the four-year period, there were 55 patients with essential oil-related seizures (EORS). 22 (40 %) had essential oil-induced seizures (EOIS) and 33 (60 %) had essential oil-provoked seizures (EOPS). The female: male ratio was 1:1.1, the age of the patients ranged from 8 months to 77 years. In the EOIS group, 95 % had generalized tonic-clonic seizures and 5% had focal impaired awareness seizures. In the EOPS group, 42.4 % had focal impaired awareness seizures, 27.3 % generalized tonic-clonic seizures, 15 % focal to bilateral tonic-clonic seizures, and 15 % focal aware motor seizures. EOs implicated were preparations containing eucalyptus and camphor.
The authors concluded that exposure to essential oils of eucalyptus and camphor is an under-recognized cause of the first and breakthrough seizure. Identifying the true causative factor will prevent unnecessary antiepileptic drug therapy and future recurrence.
These results are, of course, far from conclusive. However, they seem important enough to bear in mind and to stimulate further research. Meanwhile, patients with epilepsy might be well advised to be cautious with essential oils, particularly those from eucalyptus and camphor.