Three members of a family died and four others fell seriously ill taking nitric acid that they took for salt with rice at Soyedabad village in Sirajganj Sadar upazila on Tuesday night.
The deceased are Karimon Bewa, 60, her grandson Kawsar Ahmed, 12, and Monirul Islam, 35, son of Somed Ali.
The ill are Abdul Karim, 45, his son Shahin, 13, his daughter Koli, 8, and his wife Selina Khatun, 35. They are now undergoing treatment at Sirajganj General Hospital.
The seven people, who fell seriously sick after a short time of taking rice on the night, were taken to Sirajganj General Hospital, where the three died at around 11:00pm, said doctors, police and family sources.
They had taken nitric acid with rice and curry, thinking the acid to be salt, the surviving ones said.