Symptoms and physical findings may indicate the severity of inflammatory disease of the colon, but detailed history taking is needed to limit the wide spectrum of possible causes. Infectious causes should be ruled out before other disease is assumed to be present. No single test is sufficient to diagnose ulcerative colitis or Crohn's disease. Laboratory testing, histologic assessment, endoscopy, radiology, and bowel studies are often necessary in differential diagnosis. Because of the systemic nature of colitis, manifestations in the musculoskeletal, ocular, dermatologic, hepatobiliary, and other systems may occur and provide clues. Treatment depends on the type and severity of disease. Sulfasalazine (Azulfidine), sulfa-free 5-aminosalicylic acid compounds, and corticosteroids are mainstays of treatment of ulcerative colitis and Crohn's disease. Supportive care and judicious use of antimicrobial therapy are usually effective in colitis due to bacterial, parasitic, and sexually transmitted infections and are useful for symptoms caused by colonic ischemia and vasculitis. Colitis resulting from radiation therapy may present several years after the procedure and can be difficult to diagnose and treat. In many cases of inflammatory colon disease, especially chronic conditions, consultation with a gastroenterologist is highly recommended.