Biogenic gold nanoparticles (AuNPs) were synthesized using broccoli extract to assess their antioxidant activity, wound-healing potential, and selective anticancer effects. Green synthesis with broccoli offers an environmentally friendly way to produce stable and biocompatible nanomaterials. In this study, Brassica oleracea aqueous extract served as both the reducing and capping agent, producing AuNPs with a characteristic surface plasmon resonance peak at 560 nm and a well-defined cubic crystalline structure confirmed by XRD. TEM analysis showed uniformly dispersed, semi-spherical nanoparticles with an average size of 7.5 ± 3.6 nm. The biosynthesized AuNPs exhibited potent antioxidant activity, achieving 91.2 % DPPH scavenging at 100 µg/mL. In vivo tests demonstrated significantly faster wound healing, with approximately 90 % contraction by day 7 compared to 60 % in the control group, supported by histological evidence of increased collagen deposition and complete epithelialization. Moreover, AuNPs showed selective cytotoxicity towards HepG2 cancer cells (IC50 = 53.45 µg/mL) while maintaining over 70 % viability in normal HDF cells. This selectivity likely stems from differences in redox balance and mitochondrial vulnerability between cancer and healthy cells. Overall, the study presents broccoli-mediated AuNPs as multifunctional nanomaterials with potent antioxidant, regenerative, and targeted anticancer properties, highlighting their promising potential in biomedical applications.