I've heard that eating certain foods can cause bezoars. A bezoar (BE-zor) is a solid mass of indigestible material that accumulates in your digestive tract, sometimes causing a blockage. Bezoars usually form in the stomach, sometimes in the small intestine or, rarely, the large intestine.They can occur in children and adults.'ve heard that eating certain foods can cause bezoars. A bezoar (BE-zor) is a solid mass of indigestible material that accumulates in your digestive tract, sometimes causing a blockage. Bezoars usually form in the stomach, sometimes in the small intestine or, rarely, the large intestine.