S. japonicum, or *Schistosoma japonicum*, is a parasitic flatworm that causes schistosomiasis, a disease affecting millions of people, particularly in parts of Asia. This species primarily resides in the blood vessels of the host, where it can lay thousands of eggs, leading to various health complications. The life cycle of S. japonicum involves freshwater snails as intermediate hosts. Humans become infected through contact with contaminated water, where the larvae penetrate the skin. Effective control measures include improving sanitation, providing clean water, and administering antiparasitic medications to affected populations.