Pneumatosis cystoides intestinalis is a condition in which submucosal or subserosal gas cysts are found in the wall of the small or large bowel. Both fulminant and benign forms exist. Fulminant pneumatosis cystoides intestinalis is associated with an acute bacterial process, sepsis, and necrosis of the bowel, while benign pneumatosis cystoides intestinalis can be totally asymptomatic and observed as an incidental finding at laparotomy. Many different causes of pneumatosis cystoides intestinalis have been proposed, including mechanical and bacterial causes. A review of the literature is presented with emphasis on the etiology of pneumatosis cystoides intestinalis, which probably can be attributed to bacterial and mechanical factors. Diagnosis and different forms of therapy and their efficacy are also discussed.