How Long Does It Take Miralax To Work

Miralax is a store-bought, nonprescription laxative that is meant to stimulate bowel movements by increasing the water in your intestinal tract. It’s best used for irregularity and acute constipation in adults and children over the age of six months. If you’re dealing with constipation or irregularity of any kind, immediate relief is what you’re hoping for and if you’re taking this type of medication you’re probably wondering how long It takes for Miralax to work. This article will help clear that up as well as give you some general information about the laxative.


What Is Miralax?

In most instances, constipation and irregular bowel movements can impact your health on many levels. It can make you feel fatigued, bloated, and can even impact you cognitively. MiraLax and similar products can help clear up your irregularity and help stimulate normal bowel movements again.

Whether you’ve taken Miralax before or if you’re only considering taking it for the first time, there is a lot you should know about the laxative besides how long it takes for Miralax to work.

For starters, you shouldn’t take this laxative if you have specific types of bowel problems like obstructions or intestinal blockages. Taking Miralax when you have something like this can cause dangerous and potentially fatal side-effects. You should also avoid this if you have an eating disorder or are allergic to the main ingredient, polyethylene glycol.

Before you take MiraLax or any other laxative you should consult your doctor or another health professional. When you do, you should disclose information regarding any conditions including:

  • Ulcerative colitis
  • Kidney disease
  • Chronic nausea/vomiting
  • Irritable bowel syndrome

Other stomach issues that last longer than two weeks

  • Pregnancy

If you are taking other medications, there is a chance that they will interact badly with MiraLax. Let your doctor know of any medications you’re taking including vitamins, supplements, herbal remedies, and over-the-counter medicines. You may be asked to stop using some of them while taking Miralax.

When you take MiraLax properly, it will cause loose and possibly watery stools. It should only be used as recommended by your doctor or at least according to the package instructions. Unless your doctor says so, you shouldn’t take this laxative more than once a day. If you are taking MiraLax and aren’t seeing results after seven days of continuous, proper use it’s best to visit your doctor.

To properly take MiraLax, measure out the prescribed dose of the powder in the medicine cap on the bottle or in the given dosage cup. There will be designated lines that you can follow. Add that dose to a cold or warm drink of your choice and stir it until it dissolves. Drink the mixture right away. When not in use, store the MiraLax away from heat and moisture at room temperature.

While your doctor might prescribe a specific dose for your individual condition, the standard dose for adults suffering from constipation are 17g diluted in a full glass (8 fluid ounces) of a cold or warm beverage taken once a day. For children older than 6 months of age, a dose from 0.5 to 1.5g a day should be used for bowel preparation.

Children over 3-years-old can take 1 to 1.5g daily for three days. If you miss a dose, take it as soon as you remember it unless it’s too close to the time of your next scheduled dose. Don’t take any extra medicine in order to make up for a missed dose. If you have taken over the daily recommended dose and are feeling the effects of an overdose, call your local poison control center or see your doctor immediately.

How Long Does It Take For MiraLax To Work

If you are using Miralax to treat normal constipation or irregular bowel movements, the laxative should successfully create a bowel movement in about 12 to 72 hours. The result should be loose and potentially watery stools if you take the proper dose as recommended by the packaging or your doctor’s specific instructions.

Miralax works due to the active ingredient, propylene glycol which increases the water in your intestines. When this happens bowel movements are stimulated which can soften stool and produce the bowel movement necessary to relieve your constipation.

If you are taking MiraLax in preparation for a procedure or surgery, it might be prescribed with other laxatives in order to better prepare the bowel in a quicker and more effective manner. In these cases, the dose of the MiraLax is usually greater than the standard dose discussed earlier. This means it will likely work much faster (within one to four hours). This type of use will produce watery diarrhea in order to clean out your colon as much as possible.

No matter the dose you take, Miralax does have some side effects that you may or may not experience (some more serious than others). You should stop taking Miralax if you have signs of an allergic reaction including swelling of the lips, face, throat, and tongue, difficulty breathing, and hives.

Other serious side effects that you should seek medical help for include:

  • Severe diarrhea
  • Bloody stool
  • Rectal bleeding
  • Severe/worsening stomach pains

Other more common and less serious side effects of Miralax are:

  • Bloating/gas
  • Upset stomach
  • Dizziness
  • Increased sweating

It should also be noted that MiraLax may have different and more severe side effects in children who use it. Be sure to use this product for children under the supervision of a doctor in order to avoid any issues.


It should be noted that the information here should be taken in a general sense. There are a number of factors that can impact how long it takes for Miralax to work. Your weight, age, health, and other medications you might be taking along with the laxative. Please follow all of your doctor’s recommendations for this laxative or talk to your pharmacist if using this product on your own. Hopefully, the information here has helped you better understand this laxative and taught you about how long it takes for Miralax to work.

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Anna Smith

Hi there ! I’m Anna Smith, chief editor at Healthankering. I'm a proud mother of three passionate about health tips, beauty and ways to live healthier with more energy ! We start Healthankering to provide advanced material about not only the best ways to get healthy, but also to entertain and create a great community. Welcome aboard !

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