Fulminant gas gangrene is a rare condition, usually associated with contaminated traumatic injuries. It carries a high rate of mortality and morbidity. Also, a number of studies have implicated non-traumatic gas gangrene, associated mostly with underlying diseases that cause immunodeficiency. We report a non-traumatic fatal case of Klebsiella pneumoniae gas gangrene with small air bubbles in the left external and common iliac vein, and inferior vena cava in a previously healthy male. We would like to recommend you do not use nitrous oxide in case of gas gangrene, because it can aggravate pulmonary air embolism.