What is Citrucel? An Overview of the Gentle Fiber Laxative

October 7, 2025 •

3 min read

According to manufacturers and clinical reports, Citrucel is often recommended by physicians as a therapeutic fiber laxative. What is Citrucel? It is a brand name for an over-the-counter medication containing methylcellulose, a type of non-allergenic fiber used to treat occasional constipation and help maintain regularity.

Quick Summary

Citrucel is a bulk-forming laxative with methylcellulose, designed to treat occasional constipation and promote regularity. The soluble fiber absorbs water to increase stool bulk, producing softer, easier-to-pass bowel movements within 12 to 72 hours.

Key Points

Active Ingredient: Citrucel contains methylcellulose, a non-fermentable, soluble fiber that acts as a bulk-forming laxative.
Gas-Free Relief: The non-fermentable nature of its fiber means Citrucel provides relief with less excess gas and bloating compared to many other fiber supplements.
Mechanism: Methylcellulose absorbs water in the intestines, which increases stool bulk and moisture, leading to softer stools and easier passage.
Proper Hydration: Taking Citrucel requires a full glass of liquid with each dose to prevent a serious choking hazard caused by the fiber swelling in the throat.
Onset of Action: Users can typically expect a bowel movement to occur within 12 to 72 hours of taking the supplement.
Available Forms: Citrucel is sold in both powder and convenient caplet forms to suit different user preferences.
Short-Term Use: It is generally recommended for short-term use unless directed otherwise by a healthcare professional.

What is Methylcellulose?

At the core of Citrucel is its active ingredient, methylcellulose. This is a synthetic, non-fermentable fiber derived from cellulose, a component of plant cell walls. Unlike some other popular fiber supplements, methylcellulose is not broken down by the bacteria in your digestive system. This crucial characteristic is what allows Citrucel to provide relief from constipation without the common side effect of excess gas and bloating that can occur with fermentable fibers.

The Mechanism of Action

Methylcellulose works by a simple but effective physical process. After ingestion with plenty of fluids, the fiber absorbs water in the gastrointestinal tract. This absorption causes the methylcellulose to swell and form a soft, gel-like mass. This added bulk and moisture in the stool helps to stimulate the muscles of the intestines, prompting peristalsis—the natural muscular contractions that move waste through the colon. The result is a softer, bulkier stool that is easier to pass, providing gentle and predictable relief from constipation.

Citrucel vs. Metamucil: A Comparative Look

When considering fiber supplements, Citrucel is often compared with another market leader, Metamucil. The main difference lies in their active ingredients and the resulting digestive experience.


Feature	Citrucel	Metamucil
Active Ingredient	Methylcellulose (100% soluble fiber)	Psyllium husk (soluble and insoluble fiber)
Effect on Gas	Non-fermentable fiber, resulting in minimal to no excess gas	Psyllium husk is fermentable and can cause increased gas and bloating
Formulations	Powder (orange flavor, regular & sugar-free) and caplets	Powder (various flavors, regular & sugar-free), capsules, and wafers
Texture	Mixes smoothly in liquid, creating a less thick texture	Can create a thicker, sometimes grittier texture in liquid
Other Benefits	Contains 100% soluble fiber, which can have benefits like helping manage blood sugar and cholesterol	Contains a blend of fiber types, with soluble fiber also shown to lower cholesterol

How to Use Citrucel

Proper administration is crucial for the safety and effectiveness of Citrucel. Always follow the directions on the product label or as advised by a healthcare provider.

For Powder Form:

Measure the recommended dose of powder using the cap or scoop provided.
Mix the powder briskly into a full glass (at least 8 ounces) of cold water or other liquid.
Drink the mixture promptly before it thickens. For optimal results, drink another glass of water afterward.

For Caplet Form:

Swallow the recommended number of caplets with a full glass (at least 8 ounces) of water or another liquid.
Do not crush, chew, or dissolve the caplets, as they are designed to be swallowed whole.
Take doses as needed, but do not exceed the maximum daily dose listed on the package.

Important Considerations:

Hydration is Key: Taking Citrucel without enough liquid is a serious choking hazard, as the fiber can swell in the throat.
Timing: To avoid interfering with the absorption of other medications, take Citrucel at least 2 hours before or after other medicines.
Onset: A bowel movement should occur within 12 to 72 hours. If constipation persists for more than 7 days, discontinue use and consult a doctor.

Potential Side Effects and Safety Warnings

While Citrucel is generally well-tolerated, some side effects can occur, especially when starting treatment or increasing the dose too quickly. Most side effects are mild and temporary.

Common Side Effects:

Mild stomach cramping
Nausea
Bloating

Serious Side Effects (Seek Immediate Medical Attention):

Allergic reactions, including hives, itching, or swelling
Chest pain, vomiting, or difficulty swallowing or breathing after taking
Severe stomach cramps
Rectal bleeding

Contraindications and Precautions:

Do not use Citrucel if you have a bowel obstruction, difficulty swallowing, or symptoms of appendicitis. Consult a doctor before use if you have sudden changes in bowel habits lasting more than two weeks, or if you have abdominal pain, nausea, or vomiting.

Conclusion: Making the Right Fiber Choice

Ultimately, what is Citrucel? It is a reliable and gentle bulk-forming fiber supplement designed to alleviate occasional constipation and promote regularity with minimal gas and bloating. Its active ingredient, methylcellulose, works effectively by simply adding bulk and softening the stool, making it an excellent choice for individuals with sensitive digestive systems. While Citrucel can be a valuable tool for digestive health, it should not replace a fiber-rich diet. For persistent issues, or before long-term use, it is always best to consult a healthcare provider to ensure it is the right option for your specific needs.

For more detailed information and product specifics, consider visiting the official Citrucel website.

Frequently Asked Questions

Citrucel typically produces a bowel movement within 12 to 72 hours after the first dose. Consistent use over a few days may be necessary to restore regularity.

Citrucel is intended for short-term relief of occasional constipation. It should not be used for more than one week unless a doctor recommends long-term daily use for a specific condition.

Citrucel's methylcellulose fiber is non-fermentable, meaning it is not digested by gut bacteria. This minimizes the production of excess gas and bloating, a common side effect of some other fiber supplements.

Citrucel uses methylcellulose fiber, which causes less gas, while Metamucil uses psyllium husk, which is fermentable and can cause more gas and bloating. The choice depends on personal tolerance and preference.

Citrucel is considered a safe option for treating constipation during pregnancy, as the fiber is not absorbed by the body. However, as with any medication, pregnant individuals should consult their doctor before use.

Since Citrucel is used as needed, you can take a missed dose when you remember. Do not double up on doses. For a regular schedule, skip the missed dose if it is almost time for your next one.

Citrucel is available in two primary forms: a powder (with regular or sugar-free orange flavor) and easy-to-swallow caplets.