Violent clashes broke out between students and staff at Al-Azhar University on Tuesday morning, Al-Ahram Arabic news website reports.
Students gathered at the university headquarters and began marching towards Al-Azhar Sheikhdom to demand the university take responsibility for a mass food poisoning.
Hundreds of students went down with food poisoning at the university hostel on Monday.
On Tuesday morning, the health ministry said 540 students from Al-Azhar had been hospitalised so far.
Student union member Abdullah Abdel-Moteleb told Al-Ahram that meals served at the hostel on Monday were of noticeably poorer quality than usual. By around 6pm, dozens were suffering the effects of food poisoning and were taken to hospital, he added.
Dozens of students blocked El-Nasr Street on Monday night to protest that their repeated complaints about poor services had been ignored.
Some of the protesting students demanded the resignation of the university president and the student union released a statement demanding a prompt investigation into the incident.