Eight cases of diphyllobothriasis have been experienced in the Juntendo University Hospital. Seven of the 8 patients excreted tapeworm fragments. Eggs of Diphyllobothrium latum were found in the feces in 5 cases. One patient had a history of ingestion of raw trout (Sushi), and 2 raw salmon. One might have been infected in foreign countries, and 3 could not tell the source of infection. Bithoinol was administered orally to 7 patients. Four of the 7 excreted the worm and the scolex was recognized in three of the four. Neither recurrence nor abnormal findings have been recognized so far.