Women face unique issues when it comes to substance use, both biological (sex) and cultural (gender). This new online resource provides information on the importance of scientific research into sex and gender issues related to drug use. It includes research summaries about women and commonly abused drugs, including marijuana and prescription medications. Additionally, this new Web section summarizes the latest research related to drug use while pregnant or breastfeeding, along with what science has told us about sex and gender differences in drug addiction treatment. It also looks at other issues related to drug use, including co-occurring mental health disorders, women and violence, and the importance of including women in research.