Clonorchis sinensis, commonly known as the Chinese liver fluke, is a parasitic flatworm that primarily infects the liver of various mammals, including humans. It is transmitted through the consumption of undercooked freshwater fish that contain the larvae. Once ingested, the fluke matures in the bile ducts, leading to potential liver damage and other health issues. This parasite is prevalent in parts of East Asia, particularly in China, Korea, and Vietnam. Infection can cause symptoms such as abdominal pain, jaundice, and digestive problems. Preventive measures include proper cooking of fish and improved sanitation practices to reduce transmission.