According to a police source, students fell ill soon after eating a mid-day meal at a state-run school at Visambharchak village in Banka.
"All the students have been admitted to a government hospital and their condition is stable," a district health official P Jha said.
Angry over the incident, local residents
blocked roads and demanded action against the school authorities.
Parents told a visiting police team that students started vomiting and complained of stomachache after eating the meal, a police official said.
Widespread corruption has been reported in the mid-day meal scheme in Bihar, as government guidelines on food quality are ignored.
A few months ago, a lizard and a dead rat were found in the food cooked for a mid-day meal.