Sterile larval excretion/secretion (ES) exhibited antibacterial activity against some species of bacteria. They were shown to inhibit the growth of Gram–positive bacteria Staphylococcus aureus and Bacillus subtilis Gram–negative bacteria Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae and Fungi Geotricum candidum and Aspergillus fumigatus thus exhibited limited inhibitory effect towards Gram–positive bacteria Streptococcus pyogenes and Staphylococcus epidermidis and Gram–negative Proteous vulgaris and Fungi Syncephalastrum racemosum, Candida albicans, that effect was slowed down when challenged with secretion on a solid media but no zone of complete inhibition was detected. Growth inhibiting activity was determined in liquid growth media using the Gram-positive, Gram–negative bacterial and fungal strains as indicator organisms.