The local police were alerted, and paramedics gave Fr Coughlan a medical check.
The incident occurred on November 30 and Fr Coughlan has since recovered. He has suffered no lasting effects, the spokesman said.
While nothing was stolen, the entrance gate of the college received minor damage.
Founded in 1628, the Irish College is located in Via dei Santi Quattro in the heart of Rome, near the Baptistery of St John Lateran. It is well known by many Irish couples who have opted to marry in its chapel.
In recent years, the seminary has been home to three communities: Irish seminarians, American seminarians and clerics undertaking international postgraduate studies.