**1. Introduction**

Due to increasing the number of populations worldwide, the consumption of plastic was increased too and led to produce and generate microplastic waste. The plastics were entered into all parts of our life from clothing to cleaning products because it is a cheaper, durable, and lightweight material. Large quantities of plastics are released into rivers and oceans, which can be classified into large plastic wastes and small plastic particulates named microplastics [1].

Microplastics are defined as tiny plastic particles that form as a result of the plastic content in consumer products and the breakdown of large plastics. Once they have entered the environment become pollutants, causing harm to the environment and animal health.

Microplastics prove much more challenging to remove due to their small sizes, which are often too small to spot or grab in moving water and can remain active marine contaminants for up to 450 years. The small particles of microplastics serve as carriers for bacteria and persistent organic pollutants, which are toxic organic compounds that take years to degrade. Moreover, they consist of chemical materials that are hazardous to human and animal health in high concentrations. The humans ingest microplastics by eating marine animals that have consumed the material or through drinking water or breathing air. Therefore, it is very important to have idea and information about microplastics and how to avoid or eliminate their effect on our life.

This chapter will explain the main source and effect of microplastic on the human health.
