Every physician who has had infants under his care is entirely familiar with the cases involving extreme illness, acute nutritional disturbances, diarrhea, vomiting, dehydration, progressive loss of weight, lethargy and prostration which have gone on to fatal termination in spite of all efforts in routine and dietary treatment. The relative frequency of this type of case and the serious prognosis which accompanies it has inspired a wide search for a causative focus of infection which could be removed and the lives of these infants saved. Our attention has been _called, during the past few years, to extremely encouraging reports from different men in this country who have been working on this problem. They have found that a great majority of these infants afflicted with severe gastro-intestinal disturbances as the outstanding symptoms also have accompanying foci of infection in the ears and mastoid antra. Removal of these foci by means of mastoid antrotomies have given remarkable results in many cases showing no response to the usual medical regime of treatment. The striking results reported by Marriott, Lyman, Alden and McMahon of St. Louis, and Dean, Lierle, Jeans and Floyd of Iowa City, have been the inspiration of our investigation of similar cases in the Children's Hospital, Los Angeles. Our report is based on the results of eight cases of severe gastro-intestinal disturbances associated with mastoiditis and in which mastoid antrotomies were performed.