A 23-year-old man was admitted to our hospital due to frequent bloody watery diarrhea and lower abdominal pain.He had eaten half-roasted pork at a barbeque 7 days earlier. Abdominal CT scan showed severe mucosal swelling of the ascending, right-half transverse and sigmoid colon. A small amount of ascites in the pelvic cavity was also seen. Total colonoscopy revealed mucosal bleeding, disappearance of vascular pattern, severely edematous mucosa, and multiple erosions. In the sigmoid colon, a remarkable edematous mucosa and luminal narrowing were observed, and it closely resembled ischemic colitis. Pathological findings suggested acute ischemic changes. Enterohemorrhagic Escherichia coli (EHEC) O157 and Verotoxin (VT) type 2 were detected in fecal culture. In the present case, severe inflammatory changes were found in the left colon as well as the right. Although the reason is unknown, it seems that the systemic inflammatory state accompanying advanced hemorrhagic enterocolitis on the right side may have caused the microangiopathy on the left.