Background: Eucalyptus oil is widely used as an over-the-counter remedy for respiratory congestion, yet concentrated preparations can exert rapid neurotoxic effects. Although commonly perceived as safe, even minimal exposure through inhalation may precipitate acute symptomatic seizures in individuals without pre-existing neurological illness. Such events are frequently underrecognized in clinical practice, leading to diagnostic uncertainty and avoidable treatment escalation.
Case Presentation: A 48-year-old man with no prior medical or neurological history presented with a sudden-onset generalized tonic–clonic seizure immediately after inhaling steam containing eucalyptus oil. The convulsive episode lasted approximately two to three minutes, followed by transient post-ictal confusion. Vital signs were stable, and examination revealed a lateral tongue bite without focal neurological deficits. Laboratory investigations, including serum electrolytes, calcium, magnesium, glucose levels, and renal and hepatic panels, were within normal limits. Neuroimaging (MRI brain), cerebrospinal fluid analysis, and electroencephalography performed on day two were unremarkable. He was treated with intravenous levetiracetam and remained seizure-free during 48 hours of in-hospital monitoring. Avoidance of eucalyptus oil was advised, and the patient remained seizure-free over one year of follow-up after discontinuation of antiepileptic therapy.
Discussion: The case demonstrates the capacity of eucalyptus oil inhalation to provoke an acute symptomatic seizure in an adult with no seizure predisposition. The immediate temporal association, normal diagnostic evaluation, and absence of recurrence strongly support a toxic mechanism rather than epilepsy. Similar reports highlight that eucalyptus oil constituents can induce neuronal hyperexcitability, and inhalational exposure provides rapid access to the central nervous system. Underrecognition of this trigger may result in misclassification as idiopathic epilepsy and unnecessary long-term antiepileptic medication.
Conclusion: Eucalyptus oil exposure should be actively considered in the differential diagnosis of unexplained first-episode or breakthrough seizures. Targeted history-taking, avoidance counselling, and improved public and product-label awareness are essential to prevent recurrent or misdiagnosed events associated with this commonly used household agent.
Keywords: Eucalyptus oil; Seizures; Inhalation exposure; Essential oils; Neurotoxicity syndromes; Adult; Case Reports
How to cite this article: Gondkar SS, Subramaniam SK, Arvindraj R, Gnanaprakash C, Gopinath A, Gaddam AR, Eucalyptus Oil Inhalation-Induced Seizure: A Case Report. Int J Drug Deliv Technol. 2026;16(1s): 237-242; DOI: 10.25258/ijddt.16.1.25