The explosion caused minor injuries to many people, said the department chief Lt-General Saroj Keokajee, noting that most of the injured had been discharged from the hospital.
One woman needed surgery to remove shrapnel from her face, he said.
A home-made bomb went off at a dispensary room for commissioned officers on the first floor of the Chalermprakiat building in Phramongkutklao Army Hospital on Monday morning.