Bacillus cereus causes two types of gastrointestinal diseases: emesis and diarrhea. It produces one emetic toxin and nine different enterotoxins. In March 2008, eight of a family became sick after eating slices of raw fish. We isolated emetic toxin producing B. cereus from the stools of 6 patients and 2 subclincal humans. In this study, the presence of enterotoxin genes, such as those of haemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe), B. cereus enterotoxin T (BceT), enterotoxin FM (EntFM), cytotoxin K (cytK) and cereulide were assayed by polymerase chain reaction (PCR) methods. Their enterotoxin activities were assayed using the BCET- RPLA, Tecra ELISA kit and Hep-2 vacuole activity. Bacterial isolates were subtyped by pulsed-field gel electrophoresis (PFGE). This study demonstrates the emetic toxin-producing stains of B. cereus in clinical specimens, for the first time in the Republic of Korea. (Korean J Clin Microbiol 2009;12:48-52)