We reviewed the medical records of 62 patients with systemic small and medium-sized vessel vasculitides and gastrointestinal tract involvement followed at our institution between 1981 and 2002. This group included 46 men and 16 women (male:female ratio, 2.9), with a mean age of 48 +/- 18 years. Vasculitides were distributed as follows: 38 polyarteritis nodosa (21 related to hepatitis B virus), 11 Churg-Strauss syndrome, 6 Wegener granulomatosis, 4 microscopic polyangiitis, and 3 rheumatoid arthritis-associated vasculitis. Gastrointestinal manifestations were present at or occurred within 3 months of diagnosis in 50 (81%) patients and were mainly abdominal pain in 61 (97%), nausea or vomiting in 21 (34%), diarrhea in 17 (27%), hematochezia or melena in 10 (16%), and hematemesis in 4 (6%). Gastroduodenal ulcerations were detected endoscopically in 17 (27 %) patients, esophageal in 7 (11%), and colorectal in 6 (10%), but histologic signs of vasculitis were found in only 3 colon biopsies. Twenty-one (34%) patients had a surgical abdomen; 11 (18%) developed peritonitis, 9 (15%) had bowel perforations, 10 (16%) bowel ischemia/infarction, 4 (6%) intestinal occlusion, 6 (10%) acute appendicitis, 5 (8%) cholecystitis, and 3 (5%) acute pancreatitis. (Some patients had more than 1 condition.) Sixteen (26%) patients died.The respective 10-month and 5-year survival rates were 71% (95% confidence interval [CI], 52-90) and 56% (95% CI, 35-77) for the 21 surgical patients; and 94% (95% CI, 87-101) and 82% (95% CI, 70-94) for the 41 patients without surgical abdomen (p = 0.08). Peritonitis (hazard ratio [HR] = 4.3, p < 0.01), bowel perforations (HR = 5.7, p < 0.01), gastrointestinal ischemia or infarctions (HR = 4.1, p < 0.01), and intestinal occlusion (HR = 5.5, p < 0.01) were the only gastrointestinal manifestations significantly associated with increased mortality in multivariate analysis. For this subgroup of 15 patients, 6-month and 5-year survival rates were 60% (95% CI, 35-85) and 46% (95% CI, 19-73), respectively (p = 0.003). None of the other gastrointestinal or extraintestinal vasculitis-related symptoms, or angiographic abnormalities (seen in 67% of the 39 patients who underwent angiography), was predictive of surgical complications or poor outcome. However, prognosis has dramatically improved during the past 30 years, probably owing to better management of these more severely ill patients, with prompt surgical intervention when indicated, and the combined use of steroids and immunosuppressants.