Medically Reviewed on 9/7/2022

Generic Name: methylcellulose

Brand Name: Citrucel 

Drug Class: Laxatives, Bulk-Producing

What is methylcellulose, and what is it used for?

Methylcellulose is derived from cellulose, water-insoluble fiber that is found in the tissues of plants such as cotton, flax, and grass.

Methylcellulose is used as a bulk-producing laxative to relieve occasional constipation and to maintain regularity of bowel movements. Methylcellulose is available over the counter (OTC) as caplets, or powder that is mixed with water.

Methylcellulose is not absorbed in the digestive tract and draws a large amount of water into the colon, adding bulk to the stool and making it softer and easier to pass. The increased bulk also stimulates peristalsis, the series of gastrointestinal (GI) muscle contractions that move the GI contents. Methylcellulose is also used as an emulsifying and suspending agent in cosmetic, pharmaceutical, and chemical industries.


  • Do not take methylcellulose in the following conditions:
    • Hypersensitivity to methylcellulose
    • Gastrointestinal (GI) obstruction
    • GI ulceration or adhesions
    • Swallowing difficulties (dysphagia)
    • Fecal impaction
    • Symptoms of appendicitis or other conditions that require immediate surgical intervention (acute surgical abdomen)
    • Rectal bleeding
  • Some products may contain phenylalanine, an amino acid; avoid these products if you have phenylketonuria, a condition that causes excess phenylalanine buildup.

What are the side effects of methylcellulose?

Common side effects of methylcellulose include:

  • Excessive bowel activity
  • Gas (flatulence)
  • Fecal impaction (if taken with inadequate water)

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.


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What are the dosages of methylcellulose?


  • 500 mg


  • 2 g per scoop



  • 2 caplets up to 6 times per day; not to exceed 12 caplets per day; follow each dose with 8 oz. of water.
  • Alternatively, 1 heaping tablespoon (2 g) in 8 oz. water once per day to once every 8 hours.



Children below 6 years of age

  • Safety and efficacy not established.

Children 6-12 years old

  • 1 caplet up to 6 times per day; not to exceed 6 caplets per day
  • 1 g (½ tablespoon) in 8 oz. of cold water; may increase to 1 tablespoon once every 8 hours

Children above 12 years old

  • 2 caplets up to 6 times per day; not to exceed 12 caplets per day; follow each dose with 8 oz. of water
  • Alternatively, 1 heaping tablespoon (2 g) in 8 oz. water once per day to once every 8 hours


  • Methylcellulose is not absorbed in the gastrointestinal tract and is not toxic, but it can cause fecal impaction if taken without sufficient water.
  • Treatment of overdose may include adequate intake of water and other types of laxatives or enemas to clear fecal impaction.

What drugs interact with methylcellulose?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Methylcellulose has no known severe, serious or moderate interactions with any other drugs.
  • Mild interactions of methylcellulose include:
    • sodium picosulfate

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • Methylcellulose is not systemically absorbed and is likely safe for occasional use for constipation in pregnant or breastfeeding women.
  • Always consult with your healthcare provider before taking any supplement or OTC drug if you are pregnant or breastfeeding.

What else should I know about methylcellulose?

  • Take methylcellulose exactly as recommended, with at least 8 ounces of fluid to avoid choking.
  • Do not use methylcellulose for self-treating constipation that lasts longer than 7 days, seek medical help.
  • Do not take methylcellulose if you have abdominal pain, nausea, vomiting or sudden changes in bowel habits that last longer than two weeks.
  • If you do not have a bowel movement after use or have rectal bleeding, chest pain, vomiting, difficulty breathing or swallowing, stop taking methylcellulose and consult your physician.


Methylcellulose is water-insoluble fiber that is used as a bulk-producing laxative to relieve occasional constipation and to maintain regularity of bowel movements. Common side effects of methylcellulose include excessive bowel activity, gas (flatulence), and fecal impaction (if taken with inadequate water). Methylcellulose can cause fecal impaction if taken without sufficient water. Consult your doctor if pregnant or breastfeeding.

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Medically Reviewed on 9/7/2022