Butane is known to be a suffocating gas with narcotic activity, especially at high concentrations. Within the past five years, a few cases of sudden deaths in teenage boys who had inhaled butane, a component of gas for lighters, were investigated in the Forensic Medicine Department, Medical University of Silesia, Katowice. Analyses of biological materials secured at autopsies and evidence from places of deaths was carried out using GC/FID. Butane was found in blood, lung and brain samples of the deceased. Moreover, histopathological examinations were performed. Results of autopsies and additional analyses were appraised from the point of view of their significance and usefulness in giving medico-legal opinions on the cause of death.