All the 73 affected students from Xingzhi Middle School in the city of Lianyuan had been sent to a local hospital after they had showed symptoms of vomiting and diarrhea.
As of this evening, one of them was still being treated and four were under medical observation in hospital.
The remaining affected students have been discharged from hospital and returned to school after receiving intravenous infusion therapy, according to the Lianyuan municipal government, state-run Xinhua news agency reported.
Initial investigation by the municipal food and drug administration showed that spoiled rice noodles provided by the school cafeteria were to blame for the incident.