Polyethylene glycol (PEG) bowel-prep kits for colonoscopy can require drinking up to 4 liters of liquid, while oral sodium phosphate kits typically require about 3 liters.
Notes on verification
Multiple independent medical sources (Yale Medicine, UChicago Medicine, ACG) corroborate the volume figures for PEG and sodium phosphate bowel prep regimens, consistent with patient-education materials.
Sources
- How to Prepare for a Colonoscopy (webmd.com)
- https://www.yalemedicine.org/news/colonoscopy-prep-options (yalemedicine.org)
- https://gi.org/journals-publications/ebgi/a-new-pill-prep-for-colonoscopy/ (gi.org)
- https://www.uchicagomedicine.org/cancer/types-treatments/colorectal-cancer/screening-diagnosis/colonoscopy (uchicagomedicine.org)