50 students at Haripur School in Thakurgaon started experiencing acute stomach discomfort and vomiting after drinking water from the school's tubewell.
The students were admitted to Haripur Upazila Health Complex between 11am and 3pm.
The incident took place at Shitalpur High School in Dangipara union of Haripur upazila on Wednesday.
Shitalpur High School Head Teacher (Acting) Altafur Rahman confirmed the matter.
Altafur Rahman said: “I immediately informed the Upazila Nirbahi Officer Bahnishikha Asha, Chairman Ziaul Hasan Mukul, and Officer-in-Charge Tajul Islam.”
The students are out of danger, said Dr Asaduzzaman, resident medical officer of Haripur Upazila Health Complex.
He also mentioned that initially it was believed that there might be a harmful object in the water from the tubewell.
Upazila Secondary Education Officer Raihanul Islam Mia said, “I gave instructions to give quick treatment to the sick students.”
UNO Bahnishikha Asha said: "A formal complaint has been registered with the police station and a probe committee has been formed in this regard."
OC Tajul Islam said police are investigating the incident.