The objective of this study was to document menstrual products and devices patented and available prior to 1921 using United States patents. Patent literature starting with 1790 was searched for products specifically created for use during menstruation. The first menstrual product patent was granted in 1854; from 1854 through 1921, 185 patents were issued for menstrual products;Patent activity by sex and residency of the patentees was recorded. Further analysis of patent texts documented design changes and materials used in menstrual products. Motivating factors for menstrual product development as perceived by the patentees were examined. External factors, such as the role of medical practitioners and an expanding female labor force were also investigated. The relationship between changes in women's dress and the development of commercial products was also explored;Results from this study revealed that there were more male than female menstrual product patentees. Women represented 38.6% of all people involved in patenting menstrual products, an atypically high percentage of female patenting involvement in a product class. Six types of menstrual products were under development or improvement during this time: belts, receivers, absorbents, attaching devices, catamenial garments, and menstrual retentive cups. Although patents were discovered for the tampon, patent texts and other primary source information did not indicate tampons were used during menstruation, but were considered a surgical dressing;Available sources suggested menstrual products were more widely advertised and distributed than previously believed. Methods of distribution starting in the 1870s included mail order, door-to-door saleswomen, and drug and department stores. Advertisements in magazines disappeared after 1900, but patent activity increased. Menstrual products appeared to have been continuously advertised in wholesale drug store supply catalogs, as well as mail order catalogs. This suggests that commercial menstrual products were continuously available from one source or another, from the 1870s through 1921. (Text includes figures, complete listing of collected patents.)