Plain radiographs and computed tomographic scans obtained in a severely neutropenic patient with acute lymphoblastic leukemia and cytomegalovirus-associated enterocolitis revealed a pattern of prolonged mucosal adherence of oral contrast agent to the small bowel. This pattern was seen as long as 16 weeks after administration of contrast agent and has been seen previously only in patients who have received bone marrow transplants. Two sets of intestinal biopsy specimens contained crystals that coated denuded mucosa at the site of ulceration and later were trapped within the lamina propria. Electron diffraction and energy-dispersive radiographic analysis showed that these crystals were composed of barium sulfate.