BACKGROUND Octogen (HMX) is a polynitramine explosive closely related to hexogen, a known occupational toxin in military munitions plants. No acute human poisoning with octogen has ever been reported. METHODS A 28-year-old man with no history of epilepsy was admitted to the Emergency Department for seizures that had developed during the night after a full working day when he manually sieved large amounts of dry octogen. On admission, the clinical examination was normal and all other examinations could not substantiate the development of essential or secondary epilepsy. Elevated octogen concentrations were measured in his plasma, which confirmed occupational exposure to the explosive. CONCLUSIONS The rarity of acute human poisonings by octogen is due to the infrequent use of this explosive and, more importantly, its very low oral bioavailability. However, acute poisoning can occur, but should be easily avoided by implementing adequate preventive measures.