Three members of a family died from food poisoning and four others fell sick after taking food at Soydabad under Sadar upazila in Sirajganj yesterday.
Local sources said seven members of Abdul Karim's family fell sick shortly after having dinner on Tuesday night.
They were rushed to Sadar Hospital where Karim's mother Pariman Bewa, 60, son Kaiser, 12, and cousin Monirul, 35, died at about 1:00am.
Karim, 45, his wife Selina, 35, son Shaheen, 15, and daughter Koli, 6, were under treatment at Sadar Hospital.
Neighbours said the curry they took with rice might have been cooked with nitric acid mistaking it for salt, thus resulting in the family tragedy.
People of the village are mostly weavers and they mix nitric acid with colours for dyeing cloth.