The five member family of Ward No 2 of Jorhat town complained of stomach ache, nausea and vomiting after they had their dinner last night and were admitted to the Jorhat Medical College Hospital.
The family members complained that the chapatti tasted bitter and could have been contaminated.
The members have been identified as Piyolal Banik, Chandana Banik, Sanjoy Banik, Gitu Banik and Babu Banik.
The Jorhat Food Inspector has seized the remaining flour of which the family bought from a particular shop in the area and the shopkeeper was picked up for interrogation, sources added.