INDIANAPOLIS -- The number of people complaining of illness after eating at a northeastern Indianapolis restaurant has risen to more than 300 -- three of whom have been hospitalized -- Marion County Health Department spokesman John Althardt said Friday.

The ill told health officials that they had eaten at the Olive Garden restaurant on East 82nd Street from between Saturday and Monday. Those who became sick reported flu-like symptoms, including vomiting, diarrhea, nausea and fever, 6News' Stacia Matthews reported.

The Marion County Health Department said six Olive Garden employees called in sick on Monday. Health officials said they are working to find out the nature of the employees' illnesses, when they worked and what symptoms they had.

The health department said it still is trying to determine what caused the customers' illnesses. MCHD officials began an investigation Tuesday, inspecting the restaurant and reviewing its food-handling procedures. On Wednesday, the department's Ed Culver said the restaurant took follow-up measures and said it was safe to eat there now.

Investigators have been recording what the ill ate and collecting stool samples for analysis.

"It sometimes can take a couple of weeks," Culver said of the investigation. "We may have something before that, but I can't guarantee that."

By Wednesday, 19 customers had reported to health officials that they were ill. By Thursday, the number of people who reported illness rose to 165.

One of the ill, Heather Burdette, told 6News that she and six other people she knew became sick after they dined with her at the restaurant. She said Thursday that she still can't hold down any food.

"I don't want to eat anything," Burdette said. "The nausea comes and goes."

Health officials said most of the illnesses have resolved themselves within 36 hours.

Because some of the sick are residents of Hamilton County, the health department in that county also is investigating.

Health officials asked that anyone who became ill after eating at the restaurant should contact the Marion County Health Department at 317-221-2222 or the Hamilton County Health Department at 317-776-8500.