Ischemic colitis resulting from bowel preparation for colonoscopy is extremely rare, with only a small number of cases with polyethylene glycol having been reported. Here, we present a patient with ischemic colitis after administration of a low-volume oral sulfate solution (OSS). A 49-year-old female without any significant medical history experienced abdominal pain, vomiting, and hematochezia after ingestion of OSS. She complained of severe abdominal pain during colonoscopy, and diffuse edema, hyperemia, friability, and shallow erosions were present on the transverse, descending, and sigmoid colons. A mucosal biopsy revealed mixed lymphoid inflammatory cell infiltration with de-epithelialization, whereas an abdominal CT scan showed submucosal edema on the transverse colon. A diagnosis of ischemic colitis was made. The patient recovered with fluid and antibiotic therapy without significant sequelae. Although OSS is a clinically validated and generally safe bowel preparation agent, ischemic colitis is a rare complication that should be considered.