We studied stability of complexes of silver nanoparticles and silicon nitride before and after their interaction with liquid media and after passing through bacterial filters. According to scanning electron microscopy data, contact with fluids and passage through bacterial filters reduced the content of silver nanoparticles in complexes compared to that in initial complexes. It was shown that these differences depended on both initial characteristics of the examined samples and the used liquid media. The complex Ag/Si₃N₄ obtained after 5 silver reduction cycles and containing 15% α- and 85% β-modifications of silicon nitride (sample No. 2) was characterized by maximum stability. Culture medium produced more aggressive effect on stability of the studied complexes. We concluded that the effect of culture media on stability of silver nanoparticles-silicon nitride complexes depends on phase composition of the substrate and method of application of silver nanoparticles.