The effects of ceruletide on jejunal motor activity were studied in seven patients with postoperative intestinal atony. Jejunal pressures were recorded by three perfused catheters with orifices spaced 5 cm apart, the proximal one being positioned 10 cm beyond the ligament of Treitz. Ceruletide (0.05 microgram/Kg i.v.) significantly (p less than 0.0001) increased the number and amplitude of jejunal contractions. The action of ceruletide was most obvious the first 15-minutes after administration, then its effect diminished progressively and ceased after 65-75 minutes. The adverse reactions of ceruletide were minimal and self-limiting.