Staffordshire Police were called to the Royal Stoke University Hospital shortly before 6am on Monday due to reports of a threat in the emergency department.
A cordon was put in place at the hospital and firearms officers were deployed immediately.
A spokesman for Staffordshire Police said: "The issue was resolved shortly after following a thorough search. A uniformed presence remains in the area to provide reassurance."
A 39-year-old man from the Stoke-on-Trent area was arrested and remains in police custody. He was arrested on suspicion of causing a bomb hoax.
Tracy Bullock, chief executive of the University Hospitals of North Midlands NHS Trust, which runs Royal Stoke University Hospital, said: "I can confirm that this morning a bomb scare in our emergency department at Royal Stoke was handled quickly with the police attending and supporting our staff.
"I would like to pay tribute to everyone on duty in the department who worked calmly to support our patients during this incident which was successfully resolved with the department now back operating as normal.”