The couple was arrested after the 30-year-old victim complained Sunday that she was subjected to torture at Berhampur town, about 180 km from Bhubaneswar.
The victim, mother of two minor children, told police that her husband Ganesh Sahu was suffering from mental illness for the last six months.
Ganesh's parents were under the impression that he is ill due to witchcraft performed on him by his wife, police inspector Pragyan Paramita Padhi told IANS.
They allegedly beat her up and also forced her to consume human excreta, the officer added.
The victim also alleged that her husband and in-laws were torturing her for dowry.
Local residents rescued the victim and got her admitted to a government hospital.
"Ganesh is absconding, while his parents were arrested," police said.
The brutalities related to witchcraft, mainly against women, are common in the illiterate tribal pockets of the state. Women accused of witchcraft are often killed or paraded naked.
The state has recently approved a new law to curb such crimes with provisions of imprisonment up to seven years and penalty for such offenders.