Unlike today, 18th century medical sciences were not as advanced in scientific knowledge because the body and its functions were still a mystery. In Europe, the doctors still adhered to the dogmas of vitalists, iatrochemists, and iatrophysicists. Each follower of these "brands" of medical practice argued over which of their single causes explained all human health.
This was especially true in the great University centers in Europe. Each had their own simplistic versions of the ills of the human body. They thought that the ills of the human body were due to maladjustment of the bodies system.
Doctors based their diagnosis of illness on the ancient beliefs of "humors", bodily "tension", or other cruder doctrinaire dogmas. The practice of "bleeding" with leeches to cure illness was common during the 18th century. In fact, the practice of medicine caused more harm than good. Doctors did not sterilize their hands, or instruments.
The medicines prescribed for ailments were just as bad. In Europe anything and everything was used in the mixing and making of drugs. In America, the more, common sense approach to medicine prevailed. In fact, lay healers were better doctors than learned physicians were.
During the 18th century America, the most commonly used medicines were botanical. In fact, the most widely read material were the "herbals" catalogues, which explained where and how healing herbs grew. In addition, these materials explained their uses.
Mark Catesby, persuaded by two eminent English physicians to undertake his travels, in 1710-1719, found many therapeutic plants, including the May apple, snakeroot, ginseng, and witch-hazel, and wrote about them in his Natural History of Carolina, Florida, and the Bahamas Islands.
There were improvements in the 18th century. For instance, public health and hygiene received more attention. Population statistics were beginning to be kept and suggestions arose concerning health legislation.
The use of vaccination began in the 18th century. Smallpox was the main target for this type of therapy. Smallpox was a disfiguring and often, fatal disease. In fact, at times it was an epidemic, which ravaged the cities and countries in Europe.
Conditions for sailors also improved during this century. Scurvy was the major disease that the 18th century sailor faced. The use of fruits and vegetables improved their health. To learn more about scurvy check out the previous article on James Cook.
This is just some of the conditions and medical practices of the 18th century.
Boorstin, Daniel. The Americans: The Colonial Experience. pp. 209-219. 3 vols. New York: Vantage Press, 1958.