The Rachel Brown Papers consist of course records, writings, correspondence, memorabilia, an autograph album, biographical information, and photographs. Most of the collection consists of documents that reflect Brown's coursework as a student at Mount Holyoke College, 1916-1920. This material includes notebooks, notes, essays, assignments, and laboratory reports for courses in Biblical history and literature, chemistry, English literature, history, mathematics, philosophy and psychology, and physics. The collection also includes reports and copies of her M.S. thesis and Ph.D. dissertation that relate to her graduate work at the University of Chicago, 1920-1926. Most of the remaining material in the collection relates to Brown's collaboration with Elizabeth Lee Hazen and their discovery of the antibiotic Nystatin in 1950. This material includes correspondence, articles, and photographs pertaining to projects supported by the fund that Brown and Hazen established with income from the Nystatin patent. There are also congratulatory notes to Brown, certificates, medals, award nominations, lists of awards received, acceptance speeches, honorary degrees, and photographs of awards ceremonies all relating to Brown's achievements in science. Other information includes lists of Brown's publications, biographical articles, press releases, descriptions of Nystatin, formal photographs of Brown, and obituaries. There is also biographical information about Hazen, a formal photograph of her, and informal photographs of her with Brown. In addition, the collection includes Brown's scientific journal articles reflecting her research concerning pneumococcus and syphilis. The autograph album dates from circa 1914-circa 1920s and includes numerous autographs that appear to have been clipped from letters and other documents.

This collection is organized into seven series:

• Course Records
• Writings
• Correspondence
• Memorabilia
• Autograph Album
• Biographical Information
• Photographs