I sympathise whole heartedly with this situation. I used to abuse laxatives excessively, taking up to 50 per day. I still take around 3 or 4 per day. They are addictive if you have food issues because they help clear you out, literally. For me it was an alternative to throwing everything up, which is far worse for your health in many ways.
For me, I had to gradually decrease and learn to sit with my feelings as they are used abusively as a way of diverting feelings. It's like self-harm, the physical pain that they cause, is a relief and diverts your mind away from your real feelings, like any other addiction. Counselling and psychotherapy helped me a lot.
And I know you feel helpless, but again like the other advice from everyone else in this thread, she has to be ready to deal with it. You can show concern but just be supportive and she will come round in the end.
The fact that she was looking it up on the internet is promising. It will be a slow process but just try to keep cool about it.
Good luck
M xx