The deceased were identified as Radha Devi (40), her daughter Kumari Rekha (11), and son Kanhiyalal (13).
The police said it was not yet clear whether they committed suicide or accidentally consumed poisonous food as woman's husband Jetha Das was not in a condition to give statement.
Jetha Das was out of home due to some work when Rekha and Kanhiyalal started vomiting and complained about other health complications, police said, adding the girl died at home, while the boy breathed his last while being taken to hospital.
The bodies were handed over to the family after postmortem, they said.