Ambulances were sent to the Sheraton Hotel in downtown Raleigh just after 10 a.m. Dr. Brent Myers, Wake County's medical director, told ABC11 Eyewitness News the illness is likely food borne.
Symptoms included upset stomach, vomiting and diarrhea. About 150 students were affected out of the 1,000 attending the conference. The sick were being isolated in their rooms.
"This morning when we woke up, everybody was just, a lot of people were saying, Oh, my stomach was hurting, they had a lot of diarrhea or whatever," said participant Kenneth Moore, Jr.
Friday night, the teen attended a banquet at the Raleigh Convention Center.
"They had a salad. They had chicken with asparagus and some dumplings with peas and they had dessert," Moore recalled.
Wake County EMS evaluated about 150 people - about 20 required more extensive treatment - five went to the hospital.
"I know parents are worried. Rest assured. We are taking good care of your children. We've got a good handle on things medically and we're taking care of them," said Jeffrey Hammerstein with Wake County EMS.
Officials say they don't know the cause of the illness - but they've brought in the county epidemiologist to help find the source.
"Those numbers have not grown. We do not have people getting worse. Everything seems to be contained,' Hammerstein explained.
The Sheraton is reassuring parents.
"We don't have any indication that any other hotel guests, any employees, anybody surrounding, been involved with the hotel, are having any of the same complaints, said hotel spokesperson Kevin Johnson. "We just want to let all those parents know that we're doing all that we can to cooperate with the EMS."