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Generic Name

methylcellulose (meth el CELL u los)


Trade Name



What is methylcellulose?

This product is a synthetic chemical that loves water. It stays within the intestinal tract and is not absorbed. By attracting and holding water, it creates a softer stool. It is not a true harsh stimulant laxative which should be taken only occasionally. Methylcellulose can be taken long-term. Since it absorbs fluid, it may be helpful at times for diarrhea. It does not lower cholesterol.


What is it used for?

Methylcellulose promotes bowel regularity and is used for chronic constipation, diverticulosis and irritable bowel syndrome.


How do I take it?

Follow your physician’s instructions carefully. Mix the appropriate dose of powder in 8 ounces of cold water. Drink the mixture promptly and follow with additional water. Use this product for 2 or more days to determine its full benefit. Store this preparation at room temperature in a tightly closed container. Protect it from humidity. Keep all medications away from children. Never share your medications with anyone else.


What do I do for a missed dose?

If you miss a dose of this medicine, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and return to your regular schedule. Do not double up on this medication.


Are there interactions with food or beverages?

There are no known interactions with foods or beverages. An increase in fluid intake, a diet rich in fiber or bran and regular exercise can improve bowel regularity.


Are there interactions with other drugs?

An interaction generally means that one drug may increase or decrease the effect of another drug. Also, the more medications a person takes, the more likely there will be a drug interaction. There are no known drug interactions with methylcellulose.


Is there a problem if I have another disorder or disease?

At times, a drug may have a different or enhanced effect when other diseases are present. At other times, the drug may worsen or effect another disease. Fiber should not be used if there is a suspicion of a chronic bowel obstruction unless it is discussed with the physician. It is also best to temporarily restrict fiber after abdominal surgery and when there is a flare-up of chronic bowel disorders such as Crohn’s disease and ulcerative colitis.


What about allergies?

People who have known allergies or asthma may be at an increased risk for a reaction from any new medication. The physician should always know a patient’s allergy history. Signs of an allergic reaction are skin rash, hives and itching. Of course, a person should not take methylcellulose if there has been a previous reaction to this or other bulking agents.


What if I’m pregnant, considering pregnancy or breast-feeding?

Methylcellulose is a soluble substance that gradually takes up water. It remains within the intestinal tract and is not absorbed. This type of fiber is not a laxative which is the term the FDA makes the manufacturers use on their labels. In general, naturally occurring fiber in foods is encouraged during pregnancy. The use of a supplement such as this should be discussed with your physician.


What are the effects on sexual function?

There are no known adverse effects of methylcellulose on sexual function.


Are there other precautions?

  • The possible side effect of methylcellulose is the development of intestinal gas or flatus. It is the beneficial bacteria in the colon that create intestinal gases from certain food sources such as soluble fiber. However, methylcellulose is less likely to produce intestinal gases than psyllium (Metamucil). Insoluble fiber, found in wheat bran and cereals, does not have this side effect.
  • Always take methylcellulose with plenty of fluids. Insufficient fluid may cause the fiber to swell and cause choking or even rupture of the esophagus. Do not use methylcellulose if you have difficulty swallowing.
  • Contact your physician if constipation persists for more than a week with regular use of a bulk laxative or if rectal bleeding occurs.


How long is it safe to take methylcellulose?

Methylcellulose can be used safely long-term.


How about side effects?

Adverse reactions can occur with any drug, even over-the-counter medications. Some of these are mild such as a stomach upset, which may be avoided by taking the medication with food. Minor reactions may go away on their own but if they persist, contact the physician. For major reactions, the patient should contact the physician immediately.

For methylcellulose, the following are the observed side effects:


  • bloating
  • diarrhea
  • rumbling sounds
  • nausea
  • mild abdominal cramps


  • severe abdominal pain
  • vomiting
  • difficulty swallowing


A physician’s comment…

Hard pellet stools usually reflect a condition called diverticulosis or simple chronic constipation. An increase in dietary fiber is usually the first and, often, the only thing that needs to be done. Methylcellulose, while not increasing stool bulk like fiber, can soften hard stool pellets. When that is the only problem, this preparation can be helpful.