The term hospital derives from the Latin word hospitalis, which relates to guests and their treatment. The word reflects the early use of these institutions not merely as places of healing but as havens for the poor or for weary travelers. Hospitals first appeared in Greece as aesculapia, named after the Greek god of medicine, Aesculapius. For many centuries they developed in association with religious institutions, such as the Hindu hospitals opened in Sri Lanka in the 5th century bc and the monastery-based European hospitals of the Middle Ages (5th century to 15th century). The Hôtel Dieu in Paris, a monastic hospital founded in ad 660, is still in operation today.

 The first hospital established in the United States was Pennsylvania Hospital in Philadelphia, which was chartered in 1751 with the support of Benjamin Franklin. Although other U.S. hospitals were created in the 1700s, most people were treated for their illnesses by neighbors and friends in their homes well into the 1800s. Hospitals changed radically after the Civil War—in the early years of the war no hospitals were available to treat the thousands of soldiers who were wounded or became ill, but by the war’s end in 1865, 200 hospitals with more than 137,000 beds had opened in the northern states. In addition to the military hospitals that emerged during the Civil War, many voluntary and public hospitals appeared in the 1850s.

 Throughout the 1850s and 1860s it was far more dangerous to receive care in a hospital than at home because of poor sanitation. As many as 25 percent of patients died after surgery because hospitals of that era were overcrowded, poorly ventilated, and inadequately cleaned. The introduction of antiseptic techniques by British surgeon Joseph Lister in 1865 marked a turning point in the safety of hospitalization.

 Patient care also improved as a result of the formal training of nurses at the first U.S. nursing schools, which were founded independently in 1873 by Bellevue Hospital in New York, New Haven Hospital in Connecticut, and Boston’s Massachusetts General Hospital. The development of X rays and the clinical laboratory in the 1890s further improved the quality of care available to patients and prompted the opening of many new hospitals, including religious hospitals and hospitals that specialized in the treatment of women or children. The number of for-profit hospitals owned by doctors also increased between 1890 and 1920.

 As a result of federal legislation and funding to encourage the development of small rural hospitals, the 1940s were witness to the greatest period of growth in U.S. hospitals. Moreover, the increasing presence of health insurance, which began with the Blue Cross system in 1929, ensured that hospital services would be paid. Private insurance paid by employers expanded during the 1940s, and Medicare and Medicaid were established in the 1960s.

 In the 1980s, in an effort to rein in health care costs, some payers established a program to limit reimbursements to hospitals by determining flat fees for specific diseases or procedures, known as diagnosis-related groups (DRGs). HMOs introduced patient copayments, in which a fee is charged directly to patients for physician visits or prescription medications.

 Paralleling the increased availability of hospital services throughout the 20th century has been the transformation in the quality of care afforded by medical innovation. The introduction of sulfa drugs in 1935 and penicillin in the early 1940s greatly reduced the postsurgical infection rate. Advances in storing blood allowed for the ready availability of a blood transfusion, if needed. Diagnosis of medical conditions has been enhanced by ultrasound, computerized axial tomography (CAT, or CT) and positron emission tomography (PET) scans, magnetic resonance imaging (MRI), and the endoscope, which doubles as a highly precise, less invasive surgical instrument. New medical equipment developed in the latter part of this century has revolutionized the treatment of organ transplants, kidney failure, and cancer.