Boston (CNN) -- For more than a year, Ellen O'Donnell slept on the streets, where she was the target of theft, violence and cruelty. Her situation left her neglecting chronic health problems that threatened her survival. "It was so difficult to access [medical] services. I was totally alienated and I just couldn't relate," O'Donnell said. "I would get things stolen from me. And ... two young women tried to set me on fire. Life was just this movie and I wasn't going to bother participating anymore." Then O'Donnell stumbled upon someone she could relate to: Dr. Roseanna Means. Since 1999, Means and her team have set up clinics inside Boston shelters to offer direct, free medical care to thousands of homeless women and children.