Differential diagnosis of distended post-op colon can be misleading when based solely to imaging findings. A case report of an artefact giving the impression of faecal leak or foreign body (gossypiboma) in Spiral Computerized Tomography after colonic surgery is presented. The patient was managed conservatively due to the lack of clinical evidence of abdominal emergency. A second CT scan twenty days later revealed no findings besides minor colonic diverticulas.