Two seventh-graders were being questioned Tuesday after 34 classmates became sick after eating salsa apparently sprinkled with rat poison.
Fifteen students were taken to emergency rooms and 19 were examined at the school, said Lt. Glenda Hopkins, a Jacksonville Fire-Rescue spokeswoman.
All those taken to hospitals were treated and released, she said.
"I threw up five times, and they called an ambulance," said Chris Shoote after he was examined at Shands Jacksonville hospital.
Packets of rat poison had been spread around Paxson Middle school to control a rodent problem.
Principal Richard Scott said the two students being questioned are 12 and 15. Their names were being withheld.
School officials do not know a motive for the poisoning.
"As far as I know, it was not because of a fight," Scott said.
Medical authorities at Shands Jacksonville suspect that the students ingested small amounts of a rat poison called Talon-G. Symptoms included headaches and stomach pains, officials said.
Talon-G is used to control rats and house mice. It is fatal to humans only in large, repeated doses.