A review of scientific literature highlights the effects of microplastic pollution, focusing on environmental contamination, human uptake, and animal health impacts. Numerous studies show microplastics harm aquatic organisms. Invertebrates experience reduced feeding, fertility, slowed growth, increased oxygen consumption, and oxidative stress. Fish suffer structural damage to organs, behavioral changes, and fertility issues, with severity depending on particle size, dose, and exposure. The review concludes that microplastics pollute the seas and harm aquatic health.