Polyethylene Glycol (PEG): What It Is and How to Use It
Polyethylene glycol, or PEG, is a simple medicine that does two main things: it draws water into the gut and makes stool softer and easier to pass. You’ll see PEG as a powder you mix with water (common for constipation) or as part of stronger bowel-prep solutions for colonoscopy. It’s also used in some creams and medicines as an inactive ingredient.
How PEG Works and common forms
PEG is an osmotic laxative. That means it holds water in your bowel instead of being absorbed. The extra water softens stool and speeds transit. For everyday constipation you’ll often find PEG 3350 sold over the counter (brands like Miralax in some regions). For colonoscopy prep, you'll get larger-volume PEG solutions (GoLYTELY, MoviPrep) that empty the bowel quickly.
Powder forms: usually a scoop (17 g) mixed in 4–8 oz of water for adults once daily for constipation, but follow the package or your doctor’s directions. Prep solutions: follow your clinic’s exact instructions—timing and amount matter for a good result.
How to Use PEG Safely
Start low and simple. For occasional constipation, mix the recommended dose in room-temperature water and drink it. It usually works within 1–3 days. If you’re using it for a colonoscopy, read the instructions and finish the full dose at the times given. Don’t double doses to catch up—call your provider instead.
Watch for interactions. Combining PEG with other laxatives, high-dose diuretics, or salt-free diets increases the chance of dehydration or electrolyte changes. People with severe kidney disease, heart failure, or who are frail should check with a clinician before using PEG. Same for pregnant or breastfeeding people—ask your doctor.
Storage and buying tips: buy PEG from a reputable pharmacy or store. OTC PEG is widely available. Keep the powder dry and out of reach of kids. If something looks off—different color, odd smell—don’t use it and ask the pharmacy.
Common Side Effects & When to Call a Doctor
Most people get mild effects: gas, bloating, cramping, or loose stools. These often ease as your body adjusts. Stop and contact a clinician right away if you have severe belly pain, fever, persistent vomiting, bloody stools, signs of dehydration (dizziness, very low urine), or an allergic reaction (hives, swelling, trouble breathing).
Final practical tip: use PEG as directed and treat it like a short-term fix unless your doctor advises longer use. If constipation is frequent, ask your clinician about diet tweaks (fiber, fluids), activity, and checking medicines that might be the cause. PEG is useful, but it works best when combined with simple lifestyle steps.
