The library's collection is non-circulating and for onsite reference use only. Materials may not be checked out of the building. With the exception of a few reference resources, all materials are housed in secure, non-browsing stacks and are retrieved for users upon request.
For the most part, items in the book and scientific periodical collections are available upon request, as are the slides and photographs in the Image collection. Other types of materials, like facsimile editions and microfilms, are available to qualified researchers by prior appointment only.

The Collection is open to researchers from 10 a.m. to 6 p.m. Tuesdays, Wednesdays, and Thursdays. Appointments should be made at least 24 hours in advance by contacting the Institute via telephone, mail, or e-mail. Because of space limitations, the number of appointments available may be limited, and accommodating walk-in visitors may be difficult. For this reason, we recommend that appointments be scheduled as far in advance as possible, and ask that specific times and dates of appointments be observed. If you need to cancel or postpone an appointment, please contact us by telephone as soon as possible. Without notification, all materials will be refiled, and you will have to reschedule your appointment. Requests for access to the Historia Plantarum Collection should be by email or by calling us at 202-633-0967.

The Historia Plantarum Collection is devoted to the history of medicine, pharmacy and botany, with a particular focus on the Old World (Classical Antiquity, Byzantium, Arabic World, Middle Ages and the Renaissance) and medicinal plants. Among the fields covered are ancient botany, botanical illustration in manuscript and early printed books, history of medicine, pharmacy, and pharmacology, ethnobotany, ethnomedicine, and the history of natural sciences. With around 15,000 items, it includes many of the primary sources in the original language (printed editions), the necessary reference works for the study of such sources, the secondary literature, and many scientific journals. Books, off-prints, and journals are complemented by slides, microfilms, and “non-book” material (databases on Greek medical manuscripts, digital collections of texts and images, among others).

In recent years the Historia Plantarum Collection has been accrued with donations and purchases from the collections of Smithsonian botanists Dan Nicolson and Stanwyn Shetler; the late Smithsonian ethnobotanist Robert De Filipps (1939-2004); the historian of Arabic medicine Farid Haddad, curator of the Sami Haddad Memorial Library, which included manuscripts now at the Wellcome Library in London (UK); and archival documentation on Greek medical manuscripts of the historian of medieval pharmacy John M. Riddle, and the archives of Historian of Medieval Medicine Helen Lemay.
The MICROFILM collection includes 35mm B&W (positive or negative) microfilms of some 500 manuscripts containing Greek medical texts, dated from the early 6th through the 17th century and later, and currently preserved in collections across the globe. Microforms are in two formats: reels (35mm) and jackets (4" x 6"). Color slides (24 x 36mm) of representations of plants in Greek manuscripts complement the microfilm collection, as does also the collection of facsimile editions. One microfilm reader is available for use.

A documentary file on each of these manuscripts is also available. Data come from a personal consultation of the manuscripts in loco and include such elements as watermarks and other components of the manuscripts that need to be identified by autoptic examination.