South Carolina Corrections Department spokesman Clark Newsome says officers rescued the guard and regained control of the building at the Lee Correctional Institution in Bishopville shortly after 3 a.m. today.
The officer has been taken to a hospital for an evaluation.
Newsome says a nurse escorted by a guard was passing out medicine around 9 p.m. Tuesday when some inmates overpowered the guard. Newsome did not know how many inmates were involved, but the unit houses as many as 130 inmates in the high security prison.
He says about 100 officers blew open a door and rescued the guard after discussions with the inmates failed to resolve the situation.