iAbstractThis exploratory study aims to investigate the connection between menstrual perceptions,knowledge and education about menstruation as well as the period product choice. Using thefeminist approach, research data were gathered from three focus groups of girls between 14 and15 years old that went to the same high school in Visby (Sweden). Thematic analysis was usedto analyse the data. The findings show that the stigma surrounding menstruation affects girls’everyday lives, forcing them to hide and control their periods and emotions. This results inconstant stress in school. Menstrual concealment also has an impact on period products girlschoose. Participants were lacking knowledge regarding period products and showed nointention to use sustainable period products. Thus, menstrual knowledge is important to reducenegative perceptions and attitudes toward menstruation and period products as well as thefeeling of shame about women’s reproductive functions. Girls gain this knowledge by talkingto other females, especially moms, but also via the Internet and social media. In school, sexeducation starts too late and does not cover emotions, menstrual pain, the different periodproducts, how the menstrual cycle affects girls’ lives and the fact that menstruation is differentfor every girl.