The authors report five cases of spontaneous perforation of the large bowel for a five year period. The clinical symptoms were dominated by the feculent peritonitis. There were found no data of previous diseases of the colon during the operations and hystologically. By all five patients was manifested severe constipation before the incident. During the operation the recto sigmoid and the left colon were found plugged by stercolithes with "stone density". A hypothesis of stercoral pathogenesis of the perforations is suggested. Conclusions for the surgical tactics in the conditions of large bowel peritonitis due to benign perforation are done.