Isometric nickel copper ferrite nanoparticles with composition Ni0.5Cu0.5Fe2O4 synthesized using hydrothermal technique. Nanoparticles were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, dynamic light scattering technique, scanning electron microscopy and energy dispersive spectroscopy. The nanoparticles obtained were of ~85 nm in size. Haemolysis of blood, microbial toxicology, and teratology on chick embryos were performed using various standard biological assays. The material was found to be non haematotoxic and non-teratogenic. The Bradford’s assay showed that the level of total protein content to be insignificantly altered in the treated chick embryos. The material demonstrated an excellent antioxidant property of 75% when studied using DPPH free radical scavenging assay. The nanoparticles synthesized have shown substantial inhibition of pathogenic bacteria such as Streptococcus mutans, Bacillus substilis, Pseudomonas aeruginosa and Escherichia coli. Based on the current evidences and in comparison with the known ferrites, it was inferred that the biocompatibility and the ability of nickel copper ferrite nanoparticles to inhibit the growth of the selected pathogenic bacteria, opens the doors to a new arena for the usage of nanoparticles synthesized in clean room filters as antibacterial agents. They can also be considered for use as air filters for pathogens in nasal masks. Because of the inhibition it has caused against Streptococcus mutans, a significant contributor for tooth decay, it can be incorporated in tooth pastes, mouth washes as a potent antibacterial agent.