The liver fluke Fasciola hepatica that causes fascioliasis is a rare cause of hepatobiliary system infections. Human fascioliasis occurs after ingestion of the metacercaria on aquatic plants. We recently encountered a patient taking watercress with right lateral abdominal pain. Laboratory examinations showed eosinophilia. Abdominal CT revealed hypodense lesions in the liver. Microplate enzyme -linked immunosorbent assay (ELISA) for F. hepatica showed positive at a high titer, and diagnosis of fascioliasis was given. Triclabendazole was administered and progress was followed. After 5 months, eosinophil count had decreased and hypodense lesions in the liver on abdominal CT had reduced in size. Value of antibody against F. hepatica antigen was also decreased, showing that fascioliasis can be treated using triclabendazole.