Results of investigations on biosynthesis, characteristics and application of reuterin, low-molecular substance - derivative of glycerol, with a wide antimicrobial activity spectre, are presented. It is synthesized by Lactobacillus reuteri, living in the alimentary tract of man and animals. Working out in vitro conditions allows to start its production and application in prophylaxis and treatment of alimentary tract diseases or in the fermentation industry as a biological inhibitor of an unwanted microflora.