Polyethylene glycol (PEG)-electrolyte solution (Golytely), is most commonly used for bowel preparation before colonoscopy, as well as for barium enema and colon surgery. In this case, a 70-year-old man developed ARDS following the administration of Golytely by mouth before a scheduled colonoscopy. Aspiration of PEG-electrolyte solution was suspected, and the patient was successfully treated by BAL. Therefore, early bronchoscopy and BAL should be considered as initial treatment for PEG aspiration, because removal of PEG is most important for managing the disease.