The adequate method of antibiotic choice is reported using the laser fluorescence analysis of blood plasma with the laboratory diagnostic device “Spectrolux-MB". The method is based on the ability of micro-organisms and products of their vital functions (metabolism) to fluoresce under laser radiation. The method of fluorescence analysis has great prospects in urgent surgery and other medicine brunches due to its high information content, low cost (compared to other methods of express-diagnostics) and high speed of information acquisition.