Sahu had launched an indefinite hunger strike in front of the district collectorate on Friday demanding arrest of the killers of VHP leader Swami Laxmanananda Saraswati.
He was shifted to SCB Medical College Hospital in Cuttack last night.
"Sahu's condition is stable though his blood pressure is fluctuating," said former BJP state president Jual Oram. Sahu developed complications after he gave up food, Oram said.
Sahu, a strong follower of Saraswati, had unsuccessfully contested the 2009 Lok Sabha elections from Phulbani seat.