The environmental impact of macroplastics in the sea and soil has become a global problem, resulting in their entry into the food chain. Macroplastics become microplastics and nanoplastics over time through abrasion and degradation mechanisms. Current analytical measurements show that micro- and nanoplastics accumulate in the environment via the air and water and enter the food chain. Micro- and nanoplastics therefore have a long-term impact on the environment and biodiversity. The oral bioavailability of microplastics (> 1.5 µm) is low due to membrane barriers. In contrast, small microplastics (< 1.5 µM) and nanoplastics could probably be orally bioavailable due to their small size and ability to cross biomembranes. A potential health risk form nanoparticles can be considered relevant. Therefore, research on the oral bioavailability of nanoplastics as well as studies on molecular mechanisms of action in the organism and exposure data are needed to assess possible health risks.