Metamucil (Psyllium) For Cats

At a glance

  • About: Metamucil is a bulk-forming agent used as a laxative and to increase stool consistency in cats with chronic diarrhea.
  • Contraindications: Gastrointestinal obstruction or where immediate intestinal evacuation is required (for example, poisoning).
  • Adverse effects: Flatulence if insufficient fluid is given, increased risk of esophageal or bowel obstruction.

What is Metamucil?

Metamucil is the brand name of psyllium hydrophilic mucilloid or isabgol, a bulk-forming laxative and cholesterol-lowering product produced by Procter and Gamble. Psyllium is made from hulls of ripe Plantago ovata seeds. The seed coating of P.ovata is high in hemicellulose mucilage, which swells when it comes into contact with water.

Metamucil is a mixture of both soluble and insoluble fiber.

  • Soluble fiber absorbs water as it passes through the gastrointestinal tract to form a viscous gel. As it moves into the large intestine it increases fecal mass and softens the stool, promoting the passage of feces out of the body.
  • Insoluble fiber passes through the gastrointestinal tract undigested and adds bulk to the feces which can benefit constipated cats.

Psyllium has not been FDA approved for use with cats but is commonly prescribed by veterinarians to treat constipation and diarrhea in cats and dogs; it is available by prescription and over the counter.

Uses of Metamucil for cats


Bulk-forming laxatives are helpful in cats whose constipation is caused by too little fibre or for cats where straining to defecate poses a risk.

The small intestine doesn’t absorb psyllium, instead, it passes into the large intestine and absorbs water which forms a gel-like substance (mucilage) that adds bulk to the stool. This helps to soften hard, dry feces and increases bulk which stimulates colon contractions to move the stool out of the body via the anus.


Psyllium can also help to add bulk and firm up watery stools associated with diarrhea and inflammatory bowel disease and slows down the passage of feces through the colon.

Metamucil for cats
Metamucil image: Keith Homan/Shutterstock


The recommended dosage for cats is 1 – 4 teaspoons of unflavoured psyllium once or twice per day added to canned food. It is extremely important to ensure the cat is well hydrated while taking Metamucil as it draws fluid from the GI tract.

Do not give Metamucil (or any other over the counter medication) to your cat without first consulting a veterinarian. There are several causes of constipation that may require medical intervention.

How long before Metamucil takes effect?

Between 12 and 72 hours.

Where can I buy Metamucil?

Psyllium is available in most supermarkets, pharmacies, and health food stores under the brand name Metamucil as well as several generic names. Only use the original (unflavoured) powder.

Veterinary formulations

  • Vetasyl Fiber Tablets for Cats (Virbac)
  • Fibor (VetPlus)


Store Metamucil in a closed container at room temperature in a dry location. Keep away from excess water or humidity.

Side effects

Psyllium is generally safe but can be a potential choking hazard, therefore always ensure fresh water is available at all times. Some cats may experience bloating flatulence while taking psyllium, especially if insufficient liquid is given.


Do not give psyllium to cats with a suspected gastrointestinal blockage or fecal impaction where prompt intestinal evacuation is required.

An allergic or anaphylactic response can occur in rare cases. If your cat displays any symptoms such as itching or difficulty breathing after administration of psyllium, seek veterinary attention immediately.

Can pregnant or lactating cats take Metamucil?

As Metamucil is poorly absorbed by the gut, it should be safe to use in pregnant animals. The FDA categorises it as category B for use during pregnancy and lactation.

Drug interactions

  • May result in increased hypoglycemia (low blood sugar) in cats taking antidiabetic agents.
  • Metamucil may bind to Digoxin (used to treat congestive heart failure), and reduce absorption. Separate doses by 3 hours or more.
  • May bind to and reduce the absorption of Nitrofurantoin if given at the same time, separate doses by 3 hours or more if possible.


Should only cause an increased amount of soft or loose stools.

Frequently asked questions

How much Metamucil can a cat have?

Start the cat on 1 teaspoon added to canned food. If symptoms don’t improve, add additional Metamucil but no more than 4 teaspoons at a time. If symptoms still persist after two weeks, consult a veterinarian.

Is Metamucil safe for cats long term?

Metamucil should only be given short-term as it can lead to dehydration over an extended period.

How do I add more fiber to a cat’s diet?

Canned, unsweetened pumpkin or freshly steamed and mashed pumpkin can be added to the diet.

Veterinary formulations high in fiber include the following:

  • Hill’s Science Diet Urinary and Hairball Control – 9.3% fiber
  • Rachael Ray Nutrish Superfood Blends – 8% fiber
  • Natural Balance Original Ultra Indoor Chicken and Salmon Meal- 8%
  • IAMS Proactive Health Weight and Hairball Control – 6.5% fiber

How else can I help a cat with constipation?

Switch to a wet diet (canned, raw or dry food moistened with water), and increase water consumption. Provide clean, fresh drinking water, in multiple bowls. Some cats may prefer to drink from a water fountain.

Schedule time to play with the cat at least once a day as exercise can help to increase gastrointestinal transit time, which is the passage of food through the gastrointestinal tract.


Donald C. Plumb – Plumb’s Veterinary Drug Handbook – 9th Edition


  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio

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