Both Silver (AgNPs) and gold (AuNPs) nanoparticles are increased being utilized broadly in many industries and biomedical products to enhance their performance. However, humans are increasingly being exposed to the two metal-NPs, which also been shown to be highly potential toxic to mammals. Meta-NPs has been demonstrated to have the capability to cross biological barriers cell membranes and subsequently interact with intracellular structures. The present in vivo study assessed the toxicological potential of AgNPs and AuNPs, in 30 mature male albino rats, assigned to three groups, to receive intraperitoneal injection of 0.25 mg/kg b.w of AgNPs (G1) or AuNPs (G2) or vehicle only (G3) daily for 21 days. Liver function makers, thyroid function hormones, testosterone hormone, inflammatory biomarkers and plasma proteins as well as histological characteristics were tested. The results revealed increased liver enzymes indicating liver toxicity and injury. Liver inflammation was manifested by elevated inflammatory cytokines interleukin-6 (IL-6) and tumour-necrosis factor alpha (TNF-α). Thyroid hormones were elevated indicating hyperthyroidism, while testosterone hormone was diminished indicating their potential to cause infertility in males. However, the low-dose of AgNPs and AuNPs has no noticeable changes in histomorphologic picture of liver. In conclusion, both metal-NPs are potentially toxic, with AgNPs exhibiting a greater toxicity effect than AuNPs. Toxicity mechanisms include direct cellular injury (lysis) and induction of oxidative stress.