Background: Poor preparation for elective colonoscopy is exceedingly common in persons with spinal cord injury (SCI). This unsatisfactory outcome is likely due to long-standing difficulty with evacuation and decreased colonic motility, which may result in inadequate responses to conventional bowel preparation regimens. We determined whether the addition of neostigmine to MoviPrep before elective colonoscopy produced a higher percentage of acceptable bowel preparations in patients with SCI. Methods: Twenty-seven SCI subjects were prospectively randomized to 1 of 2 arms: low-volume polyethylene glycol-electrolyte lavage with ascorbic acid (MoviPrep) or MoviPrep plus neostigmine methylsulfate and glycopyrrolate (MoviPrep+NG); 28 able-bodied subjects received MoviPrep alone. The quality of the cleansing preparation for colonoscopy was determined by gastroenterologists "calibrated" to use the Ottawa Scoring System, with an acceptable Ottawa Score (OS) considered to be ≤3. Results: The administration of MoviPrep alone resulted in suboptimal bowel cleansing in the SCI group compared with the able-bodied group (50% vs. 89% of subjects had an acceptable OS; χ 2 =7.94, P=0.05). However, when NG was added to MoviPrep in the SCI group, it markedly improved the quality of the bowel preparation, with 85% of patients then having an acceptable OS. The use of NG resulted in minimal bloating and distention before bowel evacuation (P=0.0005), and eye and muscle twitching; these were resolved within 1 hour after NG administration. No significant differences were noted among the preparation groups for adenoma detection rate (P=0.41). Conclusions: The combination of MoviPrep+NG was safe, well tolerated, and an effective approach to prepare the bowel for elective colonoscopy in patients with SCI. The side effects of this preparation were significant compared with the other treatment groups but were considered mild and anticipated.