Introduction: Haloperidol is a frequently prescribed antipsychotic in the hospital. To our knowledge, this is the first reported case linking haloperidol to Ogilvie's syndrome.Figure 1Figure 2Case: A 42-year-old male with a history of schizophrenia and bipolar disorder presented with respiratory distress secondary to aspiration pneumonia requiring intubation in the field. He was treated for the pneumonia, however, his hospital course was complicated by persistent agitation requiring high doses of haloperidol. He was unexpectedly hard to liberate from the ventilator, but was successfully extubated 9 days into his stay. Subsequently, he developed abdominal distention with an abdominal X-ray revealed colonic ileus. Shortly after, he went into respiratory distress requiring re-intubation. He was managed supportively for the ileus, but had increasingly worsening abdominal distention over the next several days. Repeat X-ray showed persistent colonic distention, thus a CT A/P was performed, revealing dilation of the cecum to 9 cm without mechanical obstruction, consistent with Ogilvie's. Electrolytes were normal and he was not on any narcotics. Nasogastric and rectal tubes were inserted. He was made NPO, and haloperidol was discontinued. He had significant improvement over next 24 hours, and was extubated 2 days later without future issues. Discussion: Ogilvie's syndrome (OS) is an acute colonic pseudo-obstruction characterized by massive dilation of the colon without an anatomic lesion or mechanical obstruction. It typically occurs in hospitalized patients with severe illness or after surgery in conjunction with infection, medications, electrolytes abnormalities or metabolic imbalances. OS usually involves the cecum and right hemi colon, but can extend to the rectum. We report to our knowledge, the first case of haloperidol induced OS. Haloperidol is not a typical offender given its weak anticholinergic properties. Nevertheless, the increasing administration of haloperidol in the setting of his severe acute illness led to the development of OS. There were no other culprit medications or obvious causes of OS in our patient. He improved with supportive care, and required no further intervention. Fortunately, perforation is rare, occurring in 1-3% of patients. However, it is associated with a 50-71% mortality rate. Thus, prompt recognition of OS is crucial, given that perforation rates increase with cecal diameter above 10cm and if unresolved for 6 or more days.