Five Japanese men became sick after eating poisonous puffer fish, an official said, the latest victims of a delicacy seen as sophisticated by fans and crazy by others.
The men, all in their 40s and 50s, dined at a restaurant in western Wakayama city on Friday night, the city's health official said.
They were taken ill early the next day, experiencing breathing difficulties and vomiting, the official said.
"They consumed a dinner that included liver, which is regarded as toxic material," she told AFP, reading from a statement.
The city shut down the establishment for five days from Sunday, she said.
Calls to the restaurant went unanswered.
The restaurant served the banned, poisonous parts after requests from the diners, the official said.
Aficionados say the tingle that the organs leave on your lips - caused by the potent neurotoxin they contain - is part of the appeal.
Every year, several people in Japan are hospitalised after eating fugu.
In order to get a licence for serving the fish, restaurant chefs must train for years to pass a stringent exam, which includes paper and practical tests on how to distinguish poisonous parts from others.
Strict regulations are often credited with the low level of fatalities.