Eclectic medicine was a branch of American medicine which made use of botanical remedies along with other substances and physical therapy practices, popular in the latter half of the 19th and first half of the 20th centuries.
The term was coined by Constantine Samuel Rafinesque (1784–1841), a physician who lived among the Native Americans and observed their use of medicinal plants. Rafinesque used the word eclectic to refer to those physicians who employed whatever was found to be beneficial to their patients (eclectic being derived from the Greek word eklego, meaning "to choose from").
Eclectic medicine appeared as an extension of early American herbal medicine traditions, such as "Thomsonian medicine" in the early 19th century, and Native American medicine. Regular medicine at the time made extensive use of purges with calomel and other mercury-based remedies, as well as extensive bloodletting. Eclectic medicine was a direct reaction to those barbaric practices as well as the desire to exclusivize Thomsonian medicine innovations to "professionals."
Alexander Holmes Baldridge (1795–1874) suggested that the tradition of Eclectic Medicine should be called the American School of Medicine, given its American roots. It bears resemblance to Physiomedicalism, which is practiced in the United Kingdom.
In 1827, a medical tradesperson named Wooster Beach, who broke with Thomson as he believed the field needed to be professionalized, founded the United States Infirmary in New York in 1827 and the Reformed Medical College in 1829, to practice and teach "Eclectic Medicine".
The Eclectic Medical Institute in Worthington, Ohio graduated its first class in 1833. After the notorious Resurrection Riot in 1839, the school was evicted from Worthington and it settled in Cincinnati during the winter of 1842–3. The Cincinnati school, incorporated as the Eclectic Medical Institute (EMI), continued until the last class graduation in 1939 more than a century later. Over the decades, other Ohio medical schools had been merged into that institution. The American School of Medicine (Eclectic) in Cincinnati operated from 1839 to 1857, when it merged with the Eclectic Medical Institute. 
Eclectic medicine expanded during the 1840s as part of a large, populist anti-regular medical movement in North America. It used many principles of Samuel Thomson's family herbal medication but chose to train doctors in physiology and more conventional principles, along with botanical medicine. The American School of Medicine (Eclectic) trained physicians in a dozen or so privately funded medical schools, principally located in the midwestern United States. By the 1850s, several "regular" American medical tradespersons especially from the New York Academy of Medicine, had begun using herbal salves and other preparations.
The movement peaked in the 1880s and 1890s. The schools were not approved by the Flexner Report (1910), which called for medical schools to use evidence-based practices. In 1934 J. C. Hubbard, M.D., the president of the Eclectic Medical Association said:
We must choose between being absorbed by the dominant section, our professional activities dictated and controlled, our policies subject to the approval of an unfriendly, prejudiced, self-constituted authority, and soon lose our identity as the Eclectic Section of American Medicine, or adapt ourselves to the general social change and retain the old Eclectic values of individual freedom of thought and action, independence in practice and the right to use that which has stood the test of experience in our service to mankind.
The last Eclectic Medical school closed in Cincinnati in 1939. The Lloyd Library and Museum still maintains the greatest collection of books, papers and publications of the Eclectic physicians, including libraries from the Eclectic medical schools.
The contemporary herbalist Michael Moore recounts:
In 1990 I visited the Lloyd Library in Cincinnati, Ohio, where, in the basement, I found the accumulated libraries of ALL the Eclectic medical schools, shipped off to the Eclectic Medical College (the "Mother School") as, one by one, they died. Finally, even the E.M.C. died (1939) and there they all were, holding on by the slimmest thread, the writings of a discipline of medicine that survived for a century, was famous (or infamous) for its vast plant 'materia medica,' treated the patient and NOT the pathology, a sophisticated model of vitalist healing.
Major Eclectic practitioners include John Uri Lloyd, John Milton Scudder, Harvey Wickes Felter, John King, Andrew Jackson Howe, Finley Ellingwood, Frederick J. Locke, and William N. Mundy. Harvey Wickes Felter's Eclectic Materia Medica is one of several important Eclectic medical publications dating from the 1920s. It represented the last attempt to stem the tide of "standard practice medicine". This was the antithesis of the model of the rural primary care vitalist physician who was the basis for Eclectic practice.
- The History of Western Herbal Medicine, Chanchal Cabrera, 2006.
- Former Cincinnati Medical Schools and Colleges, Archives and Rare Books, University Libraries, University of Cincinnati
- John S. Haller, A Profile in Alternative Medicine: The Eclectic Medical College of Cincinnati, 1835–1942, Kent State University Press, 1999, ISBN 0-585-26220-9
- Michael Moore, "Introduction to Felter's Materia Medica"
- Flexner Report, 1910.
- President's Annual Address (1934)| Henriette's Herbal Homepage
- Lloyd Library and Museum home
- http://www.swsbm.com/homepage/ Michael Moore, Eclectic Medicine, Materia Medica and Pharmacy – classic texts, Michael Moore Website
- Felter's 1912 biography of Scudder, Howe and King
- List of publications by Eclectic physicians, scanned by David Winston