Benzodiazepine overdose has various clinical manifestation, mainly regarding the central nervous system (CNS), cardiac and respiratory side effects, but rarely results in significant morbidity and mortality. Acute benzodiazepine poisoning results in dizziness, ataxia, nystagmus, dysarthria, hypoxia, hypothermia, bradycardia, hypotension, apnea, pulmonary aspiration, respiratory depression, coma, cardiopulmonary arrest and death. Anyway, deep nonresponsive coma should be investigated for additional etiologies. On the other hand, human transmissible prion disease has a fatal outcome with no specific treatment.