<p>Every year millions of people die from bacterial infections and cancer, which is a serious global health problem. The rapid spread of antibiotic resistance among pathogenic strains of bacteria is a particular cause for concern. Bismuth nanoparticles, especially quantum dots, demonstrate high potential in the diagnosis and treatment of diseases due to their unique properties. They have antimicrobial activity both in combination with irradiation and on their own, making them a promising alternative to traditional antibiotics. In addition, bismuth nanoparticles exhibit cytotoxicity toward cancer cells, especially when exposed to infrared or X-ray radiation, making them perspective agents for cancer therapy. This review discusses various types of bismuth-containing nanoparticles, their antimicrobial and anti-tumor properties, as well as the main mechanisms of action associated with the generation of reactive oxygen species and the photo-thermal effect.</p>