Abstract: The purpose of the current study was a continuation of the evaluation of the efficacy of different preservatives ingredients of different cough syrups and which previously assessed to Air-borne microorganisms. The airborne microorganisms were characterized firstly according to their colony color and then to their DNA sequences. The identified microorganisms were inoculated into syrup A (glycerol and propylene glycol), syrup B (propylene glycol and glycerin), syrup (C) (glycerin, propylene glycol and butyl paraben), syrup D (methyl paraben and propyl paraben) and normal saline as a control which were then incubated for 24 h. Growth of microorganisms into syrup was compared by counting the CFUs from a subculture of inoculated syrup at different time. The data showed that the genome of the three isolated air-borne microbes revealed three different species and that all the combinations of the preservatives in the four studied cough syrups behaved similarly in term of efficacy towards the microbial contamination. The results revealed that the preservatives mixtures of propylene glycol with glycerol or with glycerin or with butyl paraben preservatives and the methyl paraben with propyl paraben are have efficient antimicrobial activity against Airborne microbes during the 24 h studied period.