As an emerging new class, herbal nanoparticles and especially herbal silver nanoparticles hold great potential in the field of cancer biology. Because of cancer-specific targeting, the consequently attenuated side effects and the massive anti-cancer features render nanoparticle therapeutics desirable platforms for clinically relevant drug development. In the current research, silver nanoparticles were green-formulated by the Ocimum basilicum aqueous extract. Characterization of AgNPs was studied with different techniques. The anticancer potential of silver NPs was determined using the MTT test. The exposed cells with silver NPs were determined about anti-cancer and toxicity potentials on HUVEC (normal) and cancer cells i.e. pancreatic cancer (PANC-1 and MIA PaCa-2), gastric cancer (MKN45 and KATO III), and colorectal carcinoma (HT-29 and Ramos.2G6.4C10). In the DPPH assay, the IC50 of AgNPs and butylated hydroxytoluene (BHT) were 125 and 62 mu g/mL, respectively. Malignant cell lines viability is reduced in the AgNPs presence. The IC50 of AgNPs were 238, 219, 211, 203, 154 and 151 mu g/mL against HT-29, Ramos.2G6.4C10, MKN45, KATO III, PANC-1, and MIA PaCa-2 cell lines, respectively. The above results confirm the excellent antioxidant and anti-colorectal carcinoma, anti-gastric cancer, and anti-pancreatic cancer effects of Ag NPs.