She is a public health researcher with expertise in illicit drug use and a particular interest in women. She is Vice President of the Alcohol and Drug Foundation of NSW which operates a drug and alcohol residential treatment service catering exclusively for women and their children. Her recent work has focused on integrated care and service delivery for people who inject drugs, including services specifically aimed at women, and she is a co-investigator on the Contraception in Opioid Substitution Treatment trial currently being piloted. Assistant Professor Day has more than 90 peer reviewed publications.