Every day 800,000,000 people menstruate. Yet menstruation is still seen by many as a mark of shame. We are told not to discuss it in public, that tampons and sanitary pads should be hidden away, the blood rendered invisible. In many parts of the world, poverty, culture, and religion collide, causing the taboo around menstruation to have grave consequences. Younger people who menstruate are deterred from going to school, adults from work, infections are left untreated. The shame is universal and the silence a global rule.  In It's Only Blood Anna Dahlqvist tells the shocking but always moving stories of why and how people from the United States to Uganda, Sweden to Bangladesh, are fighting back against the shame.