Dr Kafeel Khan was released on orders of a magistrate hours after his arrest Saturday allegedly for arguing with doctors and "disturbing" treatment being given to patients at the district hospital here, police said.
Khan is currently out on bail in a case related to death of infants at a state-run hospital in Gorakhpur last year.
ASP Ajay Pratap said he was arrested for arguing with doctors and "disturbing" treatment being given to patients at the district hospital here and he was later released on orders of the magistrate.
Khan left Bahraich limits Saturday night itself, he said.
His brother, Adeel Khan, said he was arrested just before he was going to address reporters on the deaths due to acute encephalitis syndrome in the state.
Khan is one of the nine accused in a case involving the deaths of several children due to alleged disruption in the supply of oxygen at the Baba Raghav Das Medical College in August 2017. He was arrested by the Uttar Pradesh Police in September 2017.
The Allahabad High Court had granted him bail in April this year.