In the advanced progress of the synthesis of metal nanoparticles, the use of a bio-mimicking approach has been extensively studied and recognised as a non-toxic method. The use of Ag-NPs synthesised from inorganic compounds using plant extracts as surfactants are quite novel. Therefore, this study was carried out by synthesising and characterising Ag-NPs using a composite leave and bark extract solution of Croton macrostachyus as a capping agent. A 1:3 composite solution exhibited small nanoparticles with a rod-like shape that were active against bacteria. In addition, Ag-NPs were observed from leaf and bark extracts of a 1:1 components, as well as sand mall NPs from leaf extract, showing that leaf extract solution contained more reducing biomolecules. Furthermore, we studied the antibacterial activity of the synthesised NPs following the disc diffusion method (by preparing gram-negative and gram-positive bacteria). Thus, the synthesised NPs were active on Streptococcus pyogen compared with Pseudomonas aeruginosa bacteria.