Editor’s Note: Guest blogger Emma Verstraete is a doctoral candidate in Archaeology at the Department of Anthropology at the University of Illinois at Urbana-Champaign.
Why would a person buy this medicine? What were they trying to treat? As a historical archaeologist who focuses on consumer medicine, I’m faced with this question more frequently than many historians of medicine. Archaeologists rarely have access to journals, letters, or other primary sources that mention specific products present in an archaeological assemblage—such as the one pictured below from my own research about the material culture of consumerism. Historians of business and economics who research drugstores or pharmacies, too, are frequently faced with daybooks that list the product being purchased and by whom, but without specific context or rationale for the purchase.

Despite differences in research methods and artifact access, archaeologists and historians frequently confront such uncertainties relating to medicine use and disease treatment. Such subjects are also often considered taboo and are therefore sometimes not as extensively discussed in the written record. These circumstances place a burden of speculation on the researcher that demands acknowledgement of personal bias and, importantly, the biases of information recorded in archives.
Many cultures and communities, for example, rely on oral traditions, which can sometimes limit a researcher’s ability to find archival sources that deal with specific folk traditions or beliefs. Historically, who has been allowed—or not been allowed—to write down knowledge can also influence possible interpretations. And the places researchers go to verify and fact check information can also have limitations. Books and manuscripts accessioned by archives or libraries and institutional collecting policies, themselves, often reflect the history and the values of the majority culture at the expense of other groups [1]. Current efforts to decolonize and diversify the archive are working to improve these issues, but such efforts are long processes.
As a small case study, this post will discuss how such biases and silences in archival sources may have led a popular 1984 article about Abraham Lincoln to arrive at incomplete and (unintentionally) biased conclusions about the Lincoln household’s use of pennyroyal, a common plant used in nineteenth-century pharmaceutical preparations, folk medicine, and herbals.