Introduction: White pepper from the Piperaceae family is a tropical berry. The phenolic amides in white pepper have significant antioxidant activities.Piperine present in it seems to reduce pain, improve breathing, reduce inflammation and improve brain function. Aim: The aim of the study was to analyse the antidiabetic and cytotoxic effect of white pepper oleoresin with selenium nanoparticles. Materials and methods: Initially white pepper oleoresin mediated selenium nanoparticles were synthesised and confirmed using UV-Visible spectrophotometer and the alpha-amylase inhibitory activity and brine shrimp lethality assay was conducted using different concentrations of the prepared white pepper oleoresin mediated selenium nanoparticles . Results and Discussion: The different concentrations of white pepper oleoresin mediated selenium nanoparticles showed an increase in the alpha amylase activity with increased concentration and the maximum activity showed was 84 % at the maximum concentration used in the study,50µL was the highest concentration , more than 5 µL ,was found to be cytotoxic effect in Brine shrimps. Conclusion: The synthesis of selenium nanoparticles using white pepper oleoresin was of reasonable cost and was convenient to carry out. Its alpha amylase inhibitory activity was promising to consider its antidiabetic potential ; Brine shrimp lethality assay showed its cytotoxic effect at higher concentrations. Hence, an appropriate quantity of white pepper oleoresin mediated selenium nanoparticles may be used for conditions such as diabetes