Mother Teresa suffered a heart attack in Rome in 1983, while visiting Pope John Paul II. After a second attack in 1989, she received an artificial pacemaker. In 1991, after a battle with pneumonia while in Mexico, she suffered further heart problems. She offered to resign her position as head of the Missionaries of Charity. But the nuns of the order, in a secret ballot, voted for her to stay. Mother Teresa agreed to continue her work as head of the order.
In April 1996, Mother Teresa fell and broke her collar bone. In August she suffered from malaria and failure of the left heart ventricle. She had heart surgery but it was clear that her health was declining. When she fell ill, she made the controversial decision to be treated at a well-equipped hospital in California instead of one of her own clinics. The Archbishop of Calcutta, Henry Sebastian D'Souza, said he ordered a priest to perform an exorcism on Mother Teresa with her permission when she was first hospitalized with cardiac problems because he thought she may be under attack by the devil.
On 13 March 1997, she stepped down from the head of Missionaries of Charity. She died on 5 September 1997.
At the time of her death, Mother Teresa's Missionaries of Charity had over 4,000 sisters, and an associated brotherhood of 300 members, operating 610 missions in 123 countries. These included hospices and homes for people with HIV/AIDS, leprosy and tuberculosis, soup kitchens, children's and family counseling programs, personal helpers, orphanages, and schools. The Missionaries of Charity were also aided by Co-Workers, who numbered over 1 million by the 1990s.