Nanoparticle (NP) synthesis is a dynamic, versatile and active field of modern nanotechnology research with numerous applications in various industries. In the current study, silver nanoparticles (AgNPs) were biosynthesized using the floral extract of Sonchus asper (Sa), a common edible and medicinal weed (native to Asia, Europe, Africa, North America and South America), which served as a reducing and stabilizing agent. The features of the biosynthesized SaAgNPs were examined using advanced characterization techniques. Their biomedical activities, comprising antibacterial, antioxidant, antidiabetic, and anti-inflammatory activities, and their biocompatibility were assessed via in vitro studies. As a result, the change of the yellow colour of the extract solution to brown after adding the aqueous AgNO₃ solution confirmed the synthesis of SaAgNPs. FTIR spectra revealed the presence of phytochemicals, which served as reducing and stabilizing agents. SEM evidenced the spherical shape of the nanoparticles, with sizes in the range of 36-80 nm. The effective DPPH radical scavenging ability, biocompatibility and anti-inflammatory potential of the SaAgNPs were shown in a concentration-dependent manner (250-1000 µg/mL). Moreover, the biosynthesized AgNPs displayed maximum inhibition zones of 13.5 mm and 12.75 mm with a significant (p < 0.0001) inhibition against E.coli and S. aureus, showing effective antibacterial potential. Our study evaluates the toxicity and safety of SaAgNPs, including their potential interaction with human health and the environment, ensuring their safe use in various biomedical applications.