Pre-colonoscopy bowel preparation intolerance: a sign of upper gastrointestinal pathology

Severe vomiting and abdominal pain were precipitated by polyethylene glycol-based gut lavage (PEG) in two patients out of 585 referred for colonoscopy in a 2 year period. Both patients had primary adenocarcinoma of the large bowel but both were also found to have gastroduodenal problems severe enough to need surgical treatment. Both cases are presented.