Ten other students took ill and were admitted to the hospital, police said.
Durga Nishad, a std 6th student, went to the washroom at the Government Higher Secondary School, Shankar Nagar, after having the mid-day meal. Other students heard her scream and found her lying unconscious inside, said Bilaspur City Superintendent of Police Madhulika Singh.
She was declared 'brought dead' at the district hospital, Singh added.
Ten other students of std 6th and 7th were also admitted to the district hospital after they complained of vomiting and uneasiness.
The condition of other students was normal and very soon they will be discharged, he said.