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Miralax Review

Miralax® is the brand name for polyethylene glycol. It also may be known as polyethylene glycol 3350. Miralax is an osmotic laxative that can be ingested for occasional constipation or colon cleansing. Become informed about any colon cleanser before using it. Many health experts recommend not using a colon cleanser too frequently.

How Does Miralax Work?
Research suggests that Miralax is made of a long molecule with a backbone of carbon and oxygen atoms. It appears to contain several hydrogen atoms too. Like other osmotic laxatives, Miralax brings water into the intestine from the surrounding tissue through osmosis. Osmosis occurs when water travels through a semi permeable membrane from an area with a low concentration of dissolved molecules to an area with a high concentration of dissolved molecules. Osmotic laxatives appear to add to the number of dissolved molecules in the intestine. Because they make the concentration of dissolved molecules in the intestine higher than the concentration of dissolved molecules in the surrounding tissue, osmotics such as Miralax appear to drive osmosis, sending water into the intestine.

At a lower intake, Miralax is commonly used as a laxative. The water that it brings into the intestines enters the colon, making the stool softer and easier to pass. Some people may use Miralax as a colon cleanser, generally by increasing intake. At a higher intake, Miralax may bring more water into the large intestine so that the bowels become completely flushed out. A doctor might recommend Miralax as a colon cleanser for a diagnostic test such as a colonoscopy or an X-rays of the colon. Some doctors suggest taking Miralax the night before the diagnostic procedure and a second intake for the morning of the diagnostic procedure.

Osmotic Laxative Side Effects

As with any osmotic colon cleanser, Miralax at higher intake may be associated with dehydration for the user. Make sure to drink plenty of fluids while performing any colon cleansing routine. Possible side effects of too high intake of any osmotic, such as Miralax, include diarrhea, thirst, and possibly even confusion. Seek medical help immediately if you take too much of any osmotic agent. In rare cases, Miralax has been associated with diarrhea and hives. The more common side effects associated with osmotics such as Miralax are bloating, nausea, cramping, and gas. Miralax may be habit forming for some people, if used too long

Possible Risks Associated with Miralax


Bloating, Gas, Cramping, Nausea, Dependency


Diarrhea, Hives

Too High Intake

Diarrhea, Thirst, Confusion

Miralax is an osmotic laxative that doctors sometimes recommend as a colon cleanser. This colon cleanser works by drawing water into the colon through osmosis. It is important to drink plenty of fluids while using osmotics such as Miralax and to not take too much.   As with many health product, there can be less-desired side effects associated with osmotic products such as Miralax.


1. Polyethylene Glycol 3350. National Center for Biotechnology Information

2. Safety Issues Regarding Colonic Cleansing for Diagnostic and Surgical Procedures. Drug Safety

3. Electrolyte Solution with Polyethylene Glycol to Cleanse the Colon for Colonoscopy or Enema. Revista de Gastroenterology de Mexico