Our ability to document a number of examples of iatrogenic lesions of the colon and rectum in three general hospitals confirms the multiplicity of these lesions as presented in the literature. It appears that the careful surgeon and his associates would well heed the old admonition known as Murphy's law, that "Anything that can go wrong will go wrong." In the daily practice of the general surgeon and proctologist, it is apparent that gentleness in approaching any anal-rectal examination for either diagnostic or therapeutic purposes is mandatory. The insertion of any foreign object, be it an examining finger, a thermometer, enema tip, or proctoscope, may subject the patient to an inadvertent injury of significant proportion. The dangers inherent in the evaluation and treatment of patients with recognized disease processes is significantly greater than that associated with routine and screening examinations. Morbidity and mortality have been shown to be associated with the barium enema as well as with the barium enema as well as with some of the newer radiologic procedures such as mesenteric angiography. The use of tap water for enemas has produced morbidity both from thermal injuries and from electrolyte depletion. Antibiotics and chemotherapeutic drugs frequently result in colon and rectal disease, and therapeutic procedures directed at organs adjacent to the colon and rectum have resulted in a number of iatrogenic lesions. This reviews confirms reports of others that iatrogenic lesions of the colon and rectum are not solely due to the physician's inexperience, as significant numbers of these lesions were the result of the diagnostic or therapeutic efforts of men of considerable experience and skill. Advanced age of the patient and diseases leading to changes in the character of the bowel wall frequently were factors in the production of these lesions. A poorly prepared bowel has led to increased morbidity and mortality associated with iatrogenic perforations. The early recognition of these lesions and prompt medical and surgical management diminishes both the morbidity and mortality associated with such injuries.