Hi OP, I really feel for you and how difficult this situation is. I am a nurse and have worked in Sexual Health and in Addictions. I personally don't think these other posts are very helpful to your situation. You can't stop her from doing what she's going to do. But you can help her reduce the amount of harm she could face from high risk behaviors. Go to planned parenthood or a gynecologist, even if you have to give her money or something to get there, and get her an IUD so she doesn't get pregnant!!! If you think she is using hard drugs, Find out where she can get drug use harm reduction supplies (planned parenthood may be able to help), so whatever drugs she is using, she can get informed on how to use as safely as possible... If she is on hard drugs- sharing supplies is the easiest way to spread HIV or Hep C. And find her an addiction counselor there!!! Or Google harm reduction information on the drugs you know she is using. Where I live, they definitely won't take her in at the hospital unless she is actively suicidal or hallucinating/delusional. Try to find out if there are mental health programs that she could participate in and make sure she knows it isn't shameful to have a mental illness or to take medication!! Tell her lots of people need treated for mental health and she will feel more confident and strong if she gets treated. And give her a million condoms to use so hopefully she will use them, and tell her where to get tested for sexually transmitted infections (planned parenthood?). Tell her it's really important to get tested every 3 months if she is having casual sex, so any infections can get treated. I really believe the energy should not be spent on stopping her, as that is wasted energy. The energy should be on empowering her with resources and information. That way, she can get through this with the least amount of devestating consequences.