Joking that he's like a pharmacist, Pope Francis is promoting prayer as medicine for the heart.

Appearing on Sunday at his studio window, Francis held up a rosary in a box designed to resemble a packet of pills, before volunteers distributed thousands of those boxes, which feature a design of a human heart.

Francis said he was recommending reciting the rosary prayer as a "spiritual medicine" that is "good for the heart."

Francis' down-to-earth way of speaking, in a style ordinary people can readily understand, is drawing larger than usual crowds to St. Peter's Square for his traditional weekly appearances. About 80,000 tourists and Romans packed the square on Sunday.