Fonds documents the Mallochs' activities related to their medical and literary work. The fonds contains notes, correpondence, commonplace books, account books, material related to publications, family memorabilia, scrapbooks, photographs, telegrams, postcards and certificates.

The fonds contains correspondence related to the Osler Library and its holdings with people such as Maude Abbott, Edward Archibald, William B. Bean, Edward Horton Bensley, Archibald Malloch, Casey Wood, as well as John Farquhar Fulton, Keeper of the Medical History Collections at Yale University's library; the fonds also contains a typescript of talks by W.W. Francis (titled "Showman's Patter") about books and other items held in the Osler Library.