The collection of the MMBM includes books from the first decade of book printing up through the 20th century and archive material. The inventory is housed in specially secured and air-conditioned archives and is professionally restored as needed. A future presentation of the inventory on the Internet is in the planning stage.
The library focuses on the following subjects: medicine, anatomy, surgery and herbal medicine, including alchemy, natural history, the theory of evolution and the history of medicine. In addition to valuable, partly old coloured originals, the library also contains later reprints and research literature from the 20th century. The collection is further expanded as needed. Handwritten documents originating from private donations of medical personalities are available in the archives.
The private library of the physician and medical historian Gustav Adolf Wehrli (1888–1949) forms the basis of the collection. Being an individual with a mind of his own, he began collecting historical medical objects, archive documents, images and books in 1915. Although he had obtained a doctorate in the history of medicine in 1920, Wehrli never became a titular professor. However, his collections were purchased by the University of Zurich in 1932 and formed the material basis for the first historical medicine institute in Switzerland. After this sale, it is suspected that Wehrli began to build his own private collections, which later remained in the family inheritance.
On 2 October 2010, the first part of this collection, numbering 263 works, was sold by auction at the second-hand book and graphics shop Falk & Falk in Zurich. With an option on the remaining parts, Dr Franz Käppeli acquired the entire two-part collection. Since then, he has expanded this core inventory of about 450 works with additional, especially valuable and rare single copies, particularly from the areas of anatomy, medicine, surgery and the natural sciences.