Compare Miralax vs. Fibercon

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Miralax
(Polyethylene Glycol)

Fibercon
(Calcium Polycarbophil)

Helps get things moving. Miralax (Polyethylene Glycol) provides effective relief of constipation without "cramping" your style.Helps get things moving. Fibercon (Calcium Polycarbophil) is a natural fiber laxative that's safe enough to take during pregnancy. Just make sure you take it with plenty of liquid.
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
5.427272727272728Miralax
Reviews for Miralax (Polyethylene Glycol)
74%
of people say Miralax (Polyethylene Glycol) is worth it
54%
say it works well
10%
say it's a big hassle
Reviews for Fibercon (Calcium Polycarbophil)
45%
29% vs. Miralax (Polyethylene Glycol)
28%
26% vs. Miralax (Polyethylene Glycol)
21%
11% vs. Miralax (Polyethylene Glycol)
Side effects
MiralaxFibercon

The Miralax FDA package insert doesn’t have numbers about how common side effects are.

More about Miralax side effects »

We haven’t found good data for Fibercon side effects.

FDA side effect reports for Fibercon »
How it works
MiralaxFibercon
Miralax (Polyethylene Glycol) is an osmotic laxative. It uses osmosis to keep more water in your intestine, which softens your stool and makes it easier to pass.Fibercon (Calcium Polycarbophil) is a fiber-based laxative. It adds bulk and moisture to your intestine, which softens stool and makes it easier to pass.
Type of medication
MiralaxFibercon
Laxative
Osmotic
Over-the-counter
Laxative
Bulk-producing
Over-the-counter
Available as
MiralaxFibercon
  • Liquid
  • Pill
Used for (click to learn more)
MiralaxFibercon
Risk factors for serious side effects
MiralaxFibercon
  • Taking with medications that cause electrolyte imbalance
  • Age 60 or older
  • Women of childbearing age
  • Age 60 or older
  • Malignancy
  • Other condition that causes blockage or narrowing of bowel
  • Taking medications that cause constipation
Detailed Miralax (Polyethylene Glycol) risks & warnings »
  • Taking with calcium supplements
  • Taking with oral bisphosphonates
  • Age 60 or older
  • Malignancy
  • Other condition that causes blockage or narrowing of bowel
  • Taking medications that cause constipation
Detailed Fibercon (Calcium Polycarbophil) risks & warnings »
Pregnancy category
MiralaxFibercon
Alcohol
No specific alcohol-related info.No specific alcohol-related info.
Food
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
Kidneys and liver
  • Ask your doctor before you take Miralax if you have nausea or vomiting, irritable bowel syndrome (IBS), kidney disease, or sudden changes in your stool for more than 2 weeks.
No specific kidneys and liver-related info.
Sex
No specific sex-related info.No specific sex-related info.
Sleep
No specific sleep-related info.No specific sleep-related info.
Weight
No specific weight-related info.No specific weight-related info.
Upsides and benefits
MiralaxFibercon
  • Miralax is the most recommended laxative by pharmacists and doctors.
  • Most people felt it was worth the hassle.
  • It's gluten and sugar free.
  • It causes little to no cramping, bloating, gas, or feelings like you "have to go right now" compared to some other medicines to treat constipation.
  • Works differently than other over-the-counter laxatives so it's a great alternative if other medicines haven't worked.
  • Some people felt Fibercon was a hassle but still worth it.
  • It's safe to use short-term during pregnancy and breast-feeding as long as you take it with plenty of liquid, but you should still check with your baby doctor first.
  • Less gas and bloating compared to psyllium laxative products.
Downsides and risks
MiralaxFibercon
  • You have to dissolve Miralax in a beverage and drink it versus taking a pill.
  • It's not for children 16 years or younger.
  • Miralax doesn't work overnight. It can take up to 2-4 days to have a bowel movement.
  • It's not recommended that you take it for more than a week, so it you haven't had any success, you'll need to call your doctor for other laxative options.
  • You may have to take Fibercon daily for 1-3 days to see full effects.
  • If you don't take it with enough liquid, it could swell and block your throat and cause choking.
  • Not the best choice for people who have swallowing problems or aren't able to drink lots of liquids.
  • Can cause heartburn, gas, and belly cramps.
Tips from our pharmacists for people taking the medication
MiralaxFibercon
  • Dissolve Miralax powder in 4 to 8 ounces of water, juice or other drink (cold or hot) once a day.
  • Works in about 1 to 3 days. Don't use for more than 1 week.
  • Miralax is available in four different size dose bottles. It also come in pre-measured single-dose packets to make dosing easier or if you travel.
  • Ask your doctor about giving it to anyone younger than 17 years.
  • Doesn't cause as much bloating, cramping or feelings like you "have to go right now" as other medicines to treat constipation.
  • Ask your doctor before you take Miralax if you have nausea or vomiting, irritable bowel syndrome (IBS), kidney disease, or sudden changes in your stool for more than 2 weeks.
  • Stop using Miralax and call your doctor if you have pain, cramping, swelling or bulging in your belly, diarrhea, rectal bleeding or find you need to use for more than 1 week.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
  • It's important to take each dose with at least 8 ounces (a full glass) of water or other liquid. Works in about 12-72 hours.
  • Don't take more than 8 caplets in a 24 hour period without asking your doctor first and not for more than one week.
  • Don't take Fibercon within 2 hours before or after taking other medicines. It may interact and affect how they work.
  • If you take Fibercon then have chest pain, vomiting, trouble breathing or swallowing, get medical help immediately.
  • Ask your doctor before taking Fibercon if you have stomach pain, nausea, vomiting or had sudden changes in your stool for more than 2 weeks.
  • Ask your doctor about giving Fibercon to anyone younger than 12 years.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
Learn more
More about MiralaxSide effectsReviews & ratingsAlternativesFDA package insert
More about FiberconSide effectsReviews & ratingsAlternativesFDA package insert