Microplastics (MPs) pollution is a burgeoning environmental issue. Microplastics can accumulate in animals and people, presenting a considerable health hazard. Polyethylene (PE), generated from petroleum, is one of the most ubiquitous polymers. As a result, its exposure metrics have steadily increased throughout the years. This study investigated PE-MPs' impact on biochemical and molecular markers in adult male albino mice. Three groups of mice were utilized: one group received distilled water as a control. In contrast, the other groups were administered oral gavage treatments of PE-MPs at dosages of 1.3 mg/kg or 0.6 mg/kg every other day for 45 days. PE-MPs significantly decreased glutathione peroxidase activity and elevated MDA levels, indicating oxidative stress. Thyroid dysfunction was additionally indicated by the reduction of serum T3 and the rise of TSH due to PE-MPs. The evident DNA damage indicated genotoxicity. The effects were dose-dependent. This study reveals that PE-MPs may induce metabolic anomalies associated with oxidative stress, thyroid dysfunction, and genomic damage. This highlights the necessity for more research to examine the health risks associated with environmental microplastics.We can concluded that ,The toxicity of microplastics is dose-dependent, indicating that increased exposure leads to heightened harm. The findings of this study offer a preliminary alert regarding the potential endocrine disruption, oxidative stress, and molecular-level effects induced by microplastics in experimental animals in light of existing apprehensions about the ecotoxicity of manmade nanomaterials.