The 88-year-old, who had part of one lung removed as a young man, experienced two acute respiratory crises on Monday.

The Vatican said the mucus was the body’s reaction to the original pneumonia infection and not a new infection, given laboratory tests don’t indicate any new bacteria. Francis remained alert, oriented and cooperated with medical personnel.

The pope rested well all night,” the Vatican said in its update from Gemelli hospital, where Francis has been hospitalized since Feb. 14. On Monday, he had coffee and breakfast and was undergoing therapy.