More than 220 people were hospitalized after eating lobsters in east Jiangxi Province, a local hospital reported on Friday.

Ruichang city residents who unsuspectingly indulged in a Thursday night lobster feast later suffered from diarrhea, vomiting, and some contracted a fever, said Gong Jinwen, a doctor who treated the sick at Renmin Hospital. Doctors speculate that E. coli could be the cause.

More than 4,000 people attended the lobster shindig, which was part of the city’s government-sponsored lobster festival.