As MH says, Education is the Key!!
Let your girl read some books on how the body functions and what casues disease. That will be better than you preaching. Reading what a real expert has to say makes a big difference. Even better is to go and listen to someone. Believe me, it makes a difference. Many years ago, I once went to a seminar on Urine Therapy. After I came back, I was ready to try it - just after hearing some real doctors and others who had practised it and reaped the rewards. Similary, if your daughter were to come across someone who could tell her that he/she had the same problems as her and cured it with liver flush, then it would automatically inspire her.