My 20 Year-old Daughter Has Been Really Sick Lately. Her

My 20 year-old daughter has been really sick lately. Her stomach hurts so bad after she eats sometimes, so she forces herself to vomit to relieve some of the pain. She is also having a lot of diarhea. Her roomate is suspicious that she is bulimic, but my daughter tells us she is not. She's had a history of intestinal/stomach problems in the past couple of years, but even after many tests, no doctor has every been able to figure her problems out. Is it bad for her to force herself to
throw up to relieve stomach pain?