Research has identified predictors of inadequate bowel preparation. Some of these predictors or risk factors are modifiable. The table below describes risk factors for inadequate bowel preparation and potential strategies to mitigate them.

Solutions to Inadequate Bowel Preparation

Type of risk factorsList of risk factorsSolutions
  • Medical

  • Prior inadequate bowel prep

  • Chronic constipation

  • Use of constipating medications like psychotropics, opioid narcotics

  • Diabetes Mellitus

  • Obesity

  • Prior resection of the colon

  • Stroke

  • Dementia

  • Cirrhosis

  • Parkinson disease

  • ≥8 active prescription medications

  • Prior abdominal surgeries like appendectomy, hysterectomy


  • Consider large volume agents alone OR

  • Consider use of large volume agents PLUS adjuncts like bisacodyl or magnesium citrate OR

  • Consider low volume agents PLUS adjuncts like bisacodyl or magnesium citrate

  • Consider intense diet restrictions prior to colonoscopy such as low fiber diet x 72hrs, clear liquid diet x 24hrs.

  • Consider intense educational and patient activation programs

  • Non-medical

  • Age > 60 years

  • Male gender

  • Single or widowed status

  • English as a 2nd language

  • Lower household income

  • Low patient activation

  • Low health literacy

  • Longer wait times

  • Medicaid insurance

  • In-patient status

  • Afternoon colonoscopies

  • Lower educational level, ≤ 12th grade education


  • Provide clear, understandable instructions.

  • Provide instructions in the patient’s language

  • Provide instructions in multiple formats (brochures, video).

  • Open communication channels.

  • Involve a family member or friend

  • Telephone re-education a day before colonoscopy.

  • Instruction reminders (stickers, alarm clocks, phone apps)