A doctor at the town hospital in Izola in southern Slovenia complained about the strange looking piece of meat in his meal after he ordered a chicken risotto in the hospital canteen.
The doctor insisted it was not chicken, and after a row with staff the piece of meat was sent for tests - which later showed it was part of a human tongue.
Health inspectors have closed the restaurant and are reviewing hygiene standards.
Managers said the small piece of tongue could have been accidentally dropped into the food by a doctor who had come into the canteen straight after treating a patient.
They also said that it could have been added to the food supplies before they were delivered to the hospital.
The spokesman told the main Slovenian daily paper Delo: "I can say clearly that we have never used patients parts in any of our dishes." (Slovenian Delo)