UROLOGISTS and radiologists have recognized for years that irritation of the urinary tract seemed to cause intestinal gas to appear in urograms; that patients with ureteral or kidney pelvis stones, pyelitis, and ureteral catheters in place suffered from meteorism. Few have published articles on this subject. A review of the recent medical literature yields little or no proof that urinary tract irritation does cause the presence of gas in the intestinal tract, though most of the authors imply that it does cause meteorism, distention, and flatus. Few, if any, state whether meteorism means gas in the stomach, small intestine, colon, or in all of these structures. The discussions of investigators are confined mainly to the cause and treatment. The purpose of this paper is to determine the incidence and amount of gas in the small intestine in a number of cases of known urinary tract irritation, and to compare this determination with the findings in a like number of cases with no known irritation. A total of 500 x-ray examinations were studied—250 of the irritative type and 250 apparently normal. Since gas in the small intestine in amounts demonstrable by x-ray examination is an abnormal condition in patients beyond infancy, information concerning its presence here is more important than in either the stomach or colon, and, therefore, our attention has been directed to gas in the small intestine. Cases classified as having urinary tract irritation had either a demonstrable ureteral or kidney pelvis stone, or a catheter present in the bladder and ureter. Many of those with a catheter were negative for urinary disease. Those cases classified as not having urinary irritation gave no roentgen or clinical evidence of recent urinary tract disease. Second-day plates in gastro-intestinal studies were used. Each patient had his meals as usual except lunch the first day which consisted of only barium and buttermilk or barium and water for some; others ate lunch after the fluoroscopic and x-ray studies were completed the first day. Practically all had their usual breakfast and dinner the first day and all had meals as usual the second day. Patients with gastro-intestinal symptoms do not have less meteorism than patients with no urinary and no gastrointestinal symptoms. Thus it will be seen that second-day gastric studies are satisfactory normals for purposes of comparison in this study. Indeed, it would be a difficult task to discover 250 adults with no urinary and no gastro-intestinal difficulties. In making the survey, each case was recorded according to the grade or amount of gas present. The usual method of four grades was used as follows: Grade I......A single loop six inches long or less. Grade II.... One loop six inches plus or two small loops. Grade III... More than two loops, each six inches or more in length. Grade IV....Multiple loops filling the abdomen.