IN THE PAST few years, numerous reports have appeared in the literature concerning the etiology and significance of the hemorrhagic intestinal lesion in Escherichia coli endotoxin shock in dogs.1-3 These reports, as well as previous studies from our laboratory, have stimulated further investigation of this lesion. It has been shown, for example, that treatment with hyperbaric oxygen alone,4 or in combination with low molecular weight dextran,5 prolongs survival in animals subjected to E coli endotoxin. It was observed that in these animals, the prolongation of survival was consistently paralleled by a delay in onset of the classic intestinal lesion (Fig 1). In studies by Alican,6 Lillehei,7,8 and others, using hydrocortisone, phenoxybenzamine (Dibenzyline), or chlorpromazine, improved survival has been noted, and in these reports, an associated protection of the small intestine occurred. In experiments recently reported, enterectomy was shown to improve survival statistics.9 In these