Sen. Mark Kirk had his gall bladder removed Monday.
The Illinois Republican's office issued a statement explaining that on Saturday morning, Kirk went to Northwestern Lake Forest Hospital with stomach pains.
"Doctors determined that, due to the fact that he had gall stones, his gall bladder needed to be removed," said the statement.
"This morning Senator Kirk underwent a successful surgery to have his gall bladder removed and is resting comfortably. His doctor expects a quick recovery."
Kirk had suffered a stroke last year and is partially paralyzed on his left side.