The ultrasonically-assisted hydroacetonic Guaiacum officinale L. bark extract (GoBE) was used to synthesize the AgNPs. The phytochemicals in the bark extract act as major capping and reducing agents and the synthesized AgNPs were investigated for in-vitro antioxidant and anticancer activities. The colour change of the reaction mixture from light brown to dark brown represents the synthesis of Guaiacum officinale bark extract silver nanoparticles (GoBE-AgNPs). An absorption peak at 410 nm was checked by UV-vis spectrophotometer. FTIR reveals functional group participation in AgNPs capping.