For over a century and a half, since the creation of the first synthetic polymer derived from cellulose, a new material of high durability, versatility, and low cost has coexisted with humanity, which has since enjoyed its benefits and suffered various consequences, whether from direct or indirect effects of this material on health. The presence in the environment and human contact with micro and nanoplastics derived from these polymers can result in acute and chronic damage, with serious health consequences for all age groups. This narrative review presents some characteristics of the different contamination routes and mechanisms of action in the human body caused mainly by the inhalation and ingestion of micro and nanoplastics, and their effects on the various organs and systems of the human body.