Many patients report many different kinds of food to worsen their symptoms weeks after successful treatment and that this may persist for years after infection.
It is possible that this is related to irritable bowel syndrome that usually develops after gastroenteritis of different nature (viral, bacterial, parasitic) or due to to secondary lactose intolerance, inability or insufficient ability to digest lactose, a sugar found in milk and milk products, that often develops after giardia infection.
Avoiding consumption of unpasteurized milk or juices, fresh vegetables and fruits that aren't piled, are measures for preventing reinfection.

Talk with her physician!

okay thank you very much, when will she be able to eat certain foods such as tomatos again ?