The interpretation of scout abdominal roentgenograms for intestinal obstruction depends chiefly on evaluation of intraluminal gas and fluid patterns. All too often it is assumed that this diagnosis is arrived at easily when gas and fluid levels or ladder patterns of distention are present in the small intestine. However, the difficulties and shortcomings inherent in this examination often are underestimated. Opinion as to the use of barium sulfate suspensions for examinations of the small intestine when intestinal obstruction is suspected still is divided. Generally such examinations are considered hazardous when a complete or strangulating obstruction exists. The danger is regarded as less when there is only partial obstruction of the small intestine, provided that the colon is clear. Difficulty also may arise in the differentiation of distended loops of small intestine from dilated colon, particularly the transverse colon. Sometimes neither the configuration nor position of the distended loops permits their