The present submitted work was aimed at and the objective thereof was the synthesis of Copper oxide (CuO) and nickel doped CuO (Ni(CuO)) nanoparticle by means of an adaptive hydrothermal chemical route wherein the doping was effected via the addition of nickel sulphate (NiSO4) to the synthesis medium at differing concentrations. The shape and the dimension ofs the nanoparticles were revealed by modern spectroscopic methods, demonstrating clustered spherical nanoparticles having an average size of 9.8 nm. The antibacterial activity of pure and doped nanoparticles has been carried out against multi-drug-resistant bacterial strains (Escherichia, coli, Klebsiella, and Bacillus subtilis) at different concentrations (500, 1000 and 1500 µg/mL). The nanoparticles (CuO and Ni(CuO)) had a marked inhibitory activity with maximum activity observed on silver impregnated particles. Cytotoxicity assays with human red blood cell indicated low haemolysis of 2, 4, and 6 percent haemolysis at higher concentrations. The nickel doping of CuO enhanced the biocompatibility of the nano particles. Moreover, the MTT assays also showed that these nanoparticles had the ability to generate reactive oxygen species (ROS) in tumor cells, when under irradiation, a factor that led to apoptosis and cell death. Such results show the antimicrobial properties and biocompatibility of CuO and Ni(CuO) nanoparticles.