"An extreme example of a saint who was truly zealous in the mortification of her flesh and senses is Saint Mary Magdalene de'Pazzi.
Born in Florence in 1566 of an aristocratic family, Caterina de'Pazzi was a religiously precocious child. At age 10 she made a vow of perpetual chastity, secretly whipped herself and wore a crown of thorns. Although her parents were unhappy with her behavior, they allowed her to enter a Carmelite convent where she chose the name of the holy harlot, Mary Magdalene. Due to the austerity of her life she soon gained a reputation for outstanding virtue. Frequently she experienced periods of 'rapture' during which she made predictions about the future. She reportedly was able to cure diseases; one procedure she followed was to lick the skin lesions of afflicted nuns, including one who was thought to have leprosy, and to suck the maggots out of skin ulcers.
At age 20 she declared that God had ordered her to eat only bread and water. Because of swelling in her feet she often crawled around the convent on all fours and kissed the feet of the bewildered nuns. Claiming that she was being hounded by devils, she frenetically and publicly whipped her body to chase them away and threw herself naked on thorn bushes until she was covered with blood. She burned her skin with hot wax and cajoled the novices in the convent to whip her and to step on her mouth.
At about age 37, emaciated and racked with coughing and pain, she took to her bed and did not leave it until she died four years later in 1607. Her painful gums were so badly infected that she could not bear to close her jaw, until her teeth fell out, one by one. Her body was covered with putrefying bed sores, but when the sisters offered to move her she warned them off for fear that by touching her body they might experience sexual desires.
Because of her virtuous life, her miraculous healing, her clairvoyance and the presence of a perfumed fragrance that emanated from her corpse, she was beatified by Pope Urban VIII in 1626. She was admitted to the company of the saints by Pope Clement IX, who issued a decree of canonization in 1668. A large statue of her holding a flagellant whip can be seen in her church in Florence where many people from around the world still come to pay her tribute."
(The extract is taken from the book "Bodies Under Siege: Self-Mutilation and Body Modification in Culture and Psychiatry" by Dr. Armando Favazza)