Accurate interpretation of the blood ethanol (EtOH) concentration at the time of death presents a difficult task since the origin of detected EtOH in postmortem cases (either in corpses or in specimens after sample collection) may vary. Headspace gas chromatography is the choice method for detecting EtOH in blood or other specimens, due to the accuracy and sensitivity it provides. Possible sources of postmortem EtOH have been the ante-mortem ingestion, the ante-mortem endogenous production and the postmortem microbial neo-formation, which has been considered the most critical factor that could complicate the results. It has been reported that EtOH could be formed postmortem in variable and non-predictable amounts, as a function of the type and number of microorganisms present either in corpses or specimens collected at autopsy. The presence of other volatiles-mostly n-propanol-has been correlated to microbial EtOH production, although the quantitative pattern between them and EtOH still remains obscure. The factors most frequently implicated in the mechanism of postmortem EtOH production in corpses have been considered the number and nature of microbes present, the availability of various types of substrates, the temperature and the time. Complication in the interpretation of blood alcohol concentration could arise due to the atypical distribution of EtOH in the body compartments after death. Specimens to blood EtOH ratios reported in the literature are presented. All the aforementioned aspects are discussed in a comprehensive way, providing a deep insight into this essential problem.