It incident started around 7:05 p.m. in the 5800 block of High St. in Rome.
An off-duty Peoria Police officer in plain clothing was on a walk when he saw two men fighting.
The officer broke it up, but then discovered one of them was bleeding severely from the stomach.
Emergency crews were called to take the man to the hospital. He's believed to be the one who started the fight.
The other man was taken into custody without incident.
No names are being released at this time.
A police report issued to WMBD 31 said the off-duty officer did not notice a knife or weapon in the scuffle, nor did it mention what led to the fight.
A woman at the scene said it had to do with "family problems."