Cardinal George is on his fifth day at the hospital, according to the Chicago Archdiocese.
A spokesperson said, "He asks that people continue to pray for him as he continues to keep people in his prayers."
In 2006, George had surgery to remove his cancerous bladder, prostate and part of his right ureter and was deemed cancer-free. The cancer returned in 2012. Earlier this month, Cardinal George announced he was undergoing another round of chemotherapy .