Artificial intelligence (AI) chatbots are being increasingly used for mental health support, information, and care. They have the potential to provide accessible support to people with mental health conditions who otherwise may not be able to access traditional forms of care. However, there are risks associated with chatbot use that can put users at risk of worsening mental health and harm. This chapter discusses how AI chatbots are being used in mental health, their effectiveness as an intervention for symptoms of anxiety, depression, and loneliness, as well as the potential for harm and recommendations for safe use for those seeking to use chatbots for mental health support.