Ileus is a blockage of the intestines caused by a lack of peristalsis. Peristalsis is the pumping action of the intestines that helps move food through the digestive system. Ileus is used to describe both full and partial blockages. Solids (food), liquids, and gases are not able to move properly through the body when ileus occurs. Bowel movement can stop due to a mechanical blockage as well. Mechanical means there is something physically lodged in the intestine that is causing the blockage.