Silver nanopaiticles (AgNPs) have been widely used in biomedical fields because of their intrinsic therapeutic properties. Here, we introduce methods of synthesizing AgNPs and discuss their physicochemical, localized surface plasmon resonance (LSPR) and toxicity properties. We also review the impact of AgNPs on human health and the environment along with the underlying mechanisms. More importantly, we highlight the newly emerging applications of AgNPs as antiviral agents, photosensitizers and/or radiosensitizers, and anticancer therapeutic agents in the treatment of leukemia, breast cancer, hepatocellular carcinoma, lung cancer, and skin and/or oral carcinoma.