Hyalophagia or hyalophagy (from Greekhyalos = glass + phagein = to eat) is the eating of glass. Primarily a pathological disorder, it is also considered a form of pica. Hyalophagia is very dangerous as the sharp glass may wound the stomach, intestines, and throat as it passes through the system. Possible causes include vitamin or mineral deficiency, underlying physical or mental illness or stress. Glass is indigestible and cannot be passed through bowel movements. If the condition goes untreated, death from infection and waste buildup can be likely.