microplastics, with a diameter < 5 mm, is widely generated for various applications such as  containers for face wash, shampoo, toothpaste, cosmetics, etc. Recently, there are many reports that these microplastics various adverse affect marine life and threaten the ecosystem. Previous reprted that microplastics can be detected in human blood and can become lodged in organs as they travel throughout the body. Furthermore, people are already ingesting through food and water and inhaling tiny particles with their breath. However, The effects of microplastics on human health are unknown. The objective of this study was to determin routes and rates of excretion with mass balance, tissue distribution, of radioactivity following administration of a single Intra-trachea of ¹⁷⁷Lu-PVC (radiolabeled polyvinyl chloride microplastics with size of 1 µm, dose of 10 mg/kg (n=5)) administrated to mice. Major organs following Intra-trachea administration to mice were collected, and was measured the amount of total radioactivity with a gamma counter. A tissue with highest exposure was lung at most of the time. Some microplastic for 0.5 to 312 hr have been found in gastrointestinal tracts. Because, when intratracheal administration, a portion may have been absorbed through the esophagus. microplastics were excreted with 53% from injected dose through the urine and feces within 312 hours after Intra-trachea administration. There is a possibility that more than 40% remain in the body. Furthermore, it is necessary to study the effects of microplastics remaining in the body on the human body through studies using radioactive isotopes with long term half life such as C-14. In vivo study, using radioactive isotepes is good tracer to find out micro amounts of microplastic in the body.