Intestinal involvement in ulcerative colitis is generally limited to the colon and rectum. We describe a life-threatening case of ulcerative enteritis occurring after colectomy. Other 53 similar cases are reported in the literature. The aim of this narrative review was to focus on ulcerative enteritis characteristics and diagnostic workup. A 25-year-old boy affected by ulcerative colitis underwent a total colectomy in an urgent setting for septic shock. Postoperative course was characterized by elevated ileostomy output, raised up to 10 L/day. Critical clinical conditions required resuscitation therapy. After exclusion of surgical complications, intestinal infections, and histologic specimen revision, the patient underwent endoscopic examination. Ileal biopsies revealed ileal localization of ulcerative colitis. Steroid treatment was finally effective. After literature revision, we classified all cases of ulcerative enteritis in three groups, according to intestinal involvement pattern and timing of clinical manifestation after operation. Out of 54 cases, 18 occurred within 1 month since colectomy (early ileitis), 10 later on (late ileitis) and 26 do not involve ileus (nonileitis). Clinical manifestation is generally severe in the first group and mild and chronic in the others. Differential diagnoses of ulcerative enteritis are represented by infectious, immunological, toxic, and ischemic disorders. Those conditions excluded, ulcerative enteritis can be easily detected by endoscopic biopsies and treated with immunosuppressive agents. Long term surveillance seems important since recurrences are described. In conclusion, clinicians should suspect ulcerative enteritis in all patients with previous colectomy history that develop unexplained gastrointestinal syndromes, in order to avoid therapeutic delay.