Problems that can occur when police officers and hospital staff are not familiar with each other or with the procedures to be followed in the hospital are discussed. These include the question of when patients must remain handcuffed, the preservation of evidence while prisoners receive emergency room care, and the question of confidentiality concerning patients' medical records. Approaches taken by hospitals and police departments in dealing with these and other problems are described. Psychiatric units usually require a higher degree of security than emergency rooms. For example, police are required to lock their ammunition in a specified secure place before entering a locked psychiatric ward at New York City's Bellevue Hospital. Hospital administrators and police departments have developed protocols to eliminate friction between the hospital staff and the police. Ongoing discussions between police department managers and hospital administrators, ride-along programs for hospital staff, and informal friendships between hospital staff and police personnel all contribute to a bond of understanding between police and hospital personnel.