The use of motorcar safety belts has reduced mortality in road accidents but has given rise to the so-called "safety belt syndrome", a new pattern of lesions the most common and most severe of which are lesions of the abdominal wall and viscera. A case of transsection of the whole abdominal wall with mesenteric tear is reported here and numerous cases of intestinal perforation have been published. Diagnosis is often difficult and delayed. Analysis of the pathophysiology of these lesions shows that most of them are caused by incorrectly placed or adjusted belts. Prevention can only result from improved education of car drivers and passengers and from the development of more efficient safety devices.