Selenium nanoparticles (SeNPs) are promising therapeutic agents with potential applications in various diseases, including cancer, inflammatory diseases, autoimmune disorders, and infectious diseases. They are effective in targeting specific cells and delivering drugs with minimal toxicity. SeNPs have shown significant anticancer properties by inducing apoptosis and cell cycle arrest, and they are also effective in reducing oxidative stress and inflammation. They have been studied for their potential in treating conditions such as diabetes, liver injury, and neurodegenerative diseases. SeNPs can be functionalized with various ligands to enhance their stability and targeting ability. They have been shown to have antibacterial, antifungal, and antiviral properties, making them a promising candidate for treating infectious diseases. SeNPs have also been explored for their potential in diagnosing and treating diseases through their antioxidant and anti-inflammatory effects. Despite their promising potential, there are still challenges in understanding their mechanisms of action and their long-term safety in clinical settings. Further research is needed to fully explore the therapeutic applications of SeNPs in various diseases.Selenium nanoparticles (SeNPs) are promising therapeutic agents with potential applications in various diseases, including cancer, inflammatory diseases, autoimmune disorders, and infectious diseases. They are effective in targeting specific cells and delivering drugs with minimal toxicity. SeNPs have shown significant anticancer properties by inducing apoptosis and cell cycle arrest, and they are also effective in reducing oxidative stress and inflammation. They have been studied for their potential in treating conditions such as diabetes, liver injury, and neurodegenerative diseases. SeNPs can be functionalized with various ligands to enhance their stability and targeting ability. They have been shown to have antibacterial, antifungal, and antiviral properties, making them a promising candidate for treating infectious diseases. SeNPs have also been explored for their potential in diagnosing and treating diseases through their antioxidant and anti-inflammatory effects. Despite their promising potential, there are still challenges in understanding their mechanisms of action and their long-term safety in clinical settings. Further research is needed to fully explore the therapeutic applications of SeNPs in various diseases.