Polyethylene Glycol Powder for Solution (MiraLAX)

Polyethylene glycol 3350 (PEG) is a polymer-based laxative formula. It’s commonly known by the brand name MiraLAX®.


What is this medication?

POLYETHYLENE GLYCOL (pol ee ETH i leen; GLYE col) prevents and treats occasional constipation. It works by increasing the amount of water your intestine absorbs. This softens the stool, making it easier to have a bowel movement. It also increases pressure, which prompts the muscles in your intestines to move stool. It belongs to a group of medications called laxatives.

This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

COMMON BRAND NAME(S): GaviLax, GIALAX, GlycoLax, Healthylax, MiraLax, Smooth LAX, Vita Health


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What should I tell my care team before I take this medication?

They need to know if you have any of these conditions:

  • History of blockage in your bowels
  • Nausea
  • Phenylketonuria
  • Stomach or intestine problem
  • Stomach pain
  • Sudden change in bowel habit lasting more than 2 weeks
  • Vomiting
  • An unusual or allergic reaction to polyethylene glycol (PEG), other medications, foods, dyes, or preservatives
  • Pregnant or trying to get pregnant
  • Breast-feeding

How should I use this medication?

Take this medication by mouth. Take it as directed on the label. Add the right dose to 4 to 8 ounces or 120 to 240 mL of water, juice, soda, coffee or tea. Do not mix this medication with foods or other liquids. Do not combine with starch-based thickeners (e.g., flour, cornstarch, arrowroot, tapioca, xanthan gum). Mix well. Drink the solution. Do not use it more often than directed.

Talk to your care team about the use of this medication in children. While it may be given to children as young as 16 years for selected conditions, precautions do apply.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.

NOTE: This medicine is only for you. Do not share this medicine with others.


What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medication?

Interactions are not expected.

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.


What should I watch for while using this medication?

Do not use for more than one week without advice from your care team. If your constipation returns, check with your care team.

Drink plenty of water while taking this medication. Drinking water helps decrease constipation.

Stop using this medication and contact your care team if you experience any rectal bleeding or do not have a bowel movement after use. These could be signs of a more serious condition.

What side effects may I notice from receiving this medication?

Side effects that you should report to your care team as soon as possible:

  • Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat

Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):

  • Bloating
  • Gas
  • Nausea
  • Stomach cramping

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Where should I keep my medication?

Keep out of the reach of children and pets.

Store at room temperature between 20 and 25 degrees C (68 and 77 degrees F). Get rid of any unused medication after the expiration date.

To get rid of medications that are no longer needed or have expired:

  • Take the medication to a medication take-back program. Check with your pharmacy or law enforcement to find a location.
  • If you cannot return the medication, check the label or package insert to see if the medication should be thrown out in the garbage or flushed down the toilet. If you are not sure, ask your care team. If it is safe to put it in the trash, pour the medication out of the container. Mix the medication with cat litter, dirt, coffee grounds, or other unwanted substance. Seal the mixture in a bag or container. Put it in the trash.

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.

Additional Common Questions

How long does it take for MiraLAX® to work?

If you’re taking MiraLAX as directed for occasional constipation, it takes an average of one to three days to start working. (This is different from when you use MiraLAX with Gatorade® as a bowel preparation for colonoscopy.) It’s a gentle and gradual process, not sudden or dramatic.

MiraLAX is an osmotic laxative, which means it works by drawing more water into your bowels. It doesn’t directly stimulate your bowels to move. Rather, the extra water adds volume as it accumulates, which increases the pressure inside. This will eventually trigger your bowels to move.

Can you take MiraLAX every day?

General guidelines state that you can take MiraLAX every day for up to a week. If you continue to need it every day for longer than that, consult a healthcare provider. They might give you a longer-term prescription, or they might suggest an alternative medication or treatment plan.

What is the best time to take MiraLAX?

There’s no recommended time of day to take MiraLAX. The time of day that you take the medication won’t necessarily determine the time of day that your bowel movement will arrive.

However, if you take it for several days in a row, you should try to take it at roughly the same time each day. This helps to ensure that you’re not taking it more or less frequently than recommended.

How much MiraLAX can you take for severe constipation?

Don’t take more than the recommended dose of MiraLAX (17 grams) without consulting a healthcare provider. It might take a few days of using MiraLAX at the recommended dose before you see results. If you still have severe constipation after taking it daily for one week, consult your provider.

Can you take MiraLAX while pregnant?

MiraLAX is safe to take while you’re pregnant. But you should consult a healthcare provider if you need to take it regularly for longer than a week. There’s a chance it could affect your water-electrolyte balance over time. Your healthcare provider will want to keep an eye on this during your pregnancy.

Constipation is common in pregnancy, and some people need medication to treat it. Healthcare providers usually recommend diet and lifestyle changes first. But if these don’t do the trick, laxatives are a reasonable next choice. Severe constipation in pregnancy can lead to hemorrhoids or anal fissures.

A note from Cleveland Clinic

Polyethylene glycol (PEG) is one of the most commonly prescribed laxatives for occasional constipation. It’s relatively gentle and safe for almost anybody. But it’s important to use it only as directed. If you have severe or chronic constipation, consult your provider. You might need a different treatment plan.

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Note: Introduction and Additional Common Questions written and medically approved by Cleveland Clinic professionals.

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