Gold nanoparticles (AuNPs) is the one of nanodrug carriers that have been popular in the current trend. To prepare AuNPs for biomedical applications, many techniques have been developed. However, both physical and chemical methods may cause energy consuming and toxic residues so green synthesis would be the most appropriate method for the preparation of AuNPs. The green synthesis of AuNPs could be provided by utilizing of fungi, bacteria and plant. In this work, we focused to use plant latex as reducing and stabilizing agents for the synthesis of AuNPs. The latex was collected from Cryptolepis buchanani, a folk medicinal plant in Thailand. By utilizing this plant latex in the synthesis of AuNPs, the latex was not only expected the role in the synthesis of AuNPs but also biological activity. The synthesis of AuNPs by using C. buchanani latex was performed by optimizing the reaction parameters. The AuNPs obtained from optimum condition were characterized by UV-Vis spectrophotometry, Transmission electrons microscope, Dynamic light scattering and Fourier-transform infrared spectroscopy. The synthesized AuNPs exhibited the SPR band at 510 nm which also related to the spherical shape of AuNPs with the size around 5 nm. Moreover, the biological activity evaluation of synthesized were also done toward anti-cancer and anti-inflammatory.