Metamucil (Psyllium) For Cats

At a glance

  • 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 (sill-i-yum hydr-droe-fill-ik myoo-sill-oid), a bulk-forming laxative and cholesterol-lowering product and produced by Procter and Gamble. Psyllium is made from the ripe seeds of various Plantago species. The seed coating is high in hemicellulose mucilage, which swells in the presence of water.

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.



Bulk-forming laxatives are helpful in cats whose constipation is caused by too little fibre or 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 a large, soft stool stimulates intestinal contractions (peristalsis) and increase intestinal transit time to move the stool along and 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.


The recommended dosage for cats is 1 – 4 teaspoons of unflavoured psyllium once or twice per day added to wet cat food. Be sure the cat is properly hydrated.

Always make sure the cat has plenty of clean water to take while taking Metamucil.

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 which 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.

There are also veterinary formulations available.


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 of 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 little absorption 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 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.


If the cat’s condition worsens or does not improve, stop product administration and consult your veterinarian.

Bran and pumpkin are also bulk-forming laxatives which can be used to treat constipation and diarrhea in cats.

Exercise is important in all cats, especially constipated cats.


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