Patients receiving exogenous corticosteroids may develop iatrogenic adrenal insufficiency, with resultant nausea, emesis, and abdominal distension if perioperative “stress steroid” dosages are inadequate. To investigate these gastrointestinal disturbances, motility measurements were obtained using perfused catheters in 10 dogs before steroid treatment (control), during administration of high-dose corticosteroids, and daily during 5 days of abrupt withdrawal. Withdrawal was characterized by a significant disruption in normal antral, duodenal, and jejunal motility with a prolongation of the migrating motor complex (MMC) and phases I and II, but not III (I = quiescence, II = irregular activity, and III = regular activity). Retrograde giant contractions (RGCs), giant migrating contractions (GMCs), and/or “intestinal fibrillation” were also observed during the first two withdrawal days. Adrenal weights and morphology did not change. We conclude: (1) high-dose corticosteroids can induce profound adrenal suppression in dogs without morphologic changes within 3 weeks; (2) high-dose steroid administration enhances gastrointestinal motility; and (3) acute withdrawal causes disappearance or shortening of MMC and the development of RGCs and GMCs with associated emesis.