The patients, aged from 3 to 18 years old, suffered from diarrhoea, nausea, stomach pains and fever since Sunday in Lianhua County, according to the county health bureau.
Initial investigations suggest that the victims contracted a bacterial infection from food or water poisoning, the state-run Xinhua news agency said.
The affected people are in stable condition, with 21 of them still hospitalised.
Police is investigating the cause of the illness, the bureau said.