Metamucil for Cats: What You Need To Know

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Metamucil for cats feature

You are cleaning out the litterbox and notice that your cat’s stool is small, dry, and hard. Your cat is probably constipated. The first treatment most people think of is Metamucil. It works for humans, so does it work for cats, too?

The short answer is that yes, Metamucil can work for cats. Keep reading for the details on safety, dosing, and more.

But before we talk about Metamucil, let’s learn a little more about constipation in cats.

Symptoms and Signs of Constipation in Cats

Constipation is defined as infrequent bowel movements or difficulty in passing feces. You may see your cat straining in the litterbox with an arched back and a painful meow. The poop in the box may appear hard and dry, sometimes there is blood on the stool. With some cats, your cat may have diarrhea. This can happen when there is a fecal impaction and watery diarrhea passes around the fecal ball.

Many cats are private about their bowel movements and run away whenever anyone approaches the litterbox. This can make it hard for cat owners to realize their cat is suffering from constipation.

Make it a habit to clean the litter box every one to two days. If you notice a decrease in the amount of poop in the box or if the stool is very dry and small, your cat may be constipated.

When cats have a hard time pooping, they may associate the pain and difficulty with the litter box. It is not uncommon for cats suffering from constipation to defecate outside the litter box. It may be next to the box, in their bed, or in a corner of your house.

Causes of Constipation in Cats

Constipated cats are often dehydrated. One of the colon’s jobs is to absorb water from waste material. If your kitty is dehydrated, the colon pulls more water out of the waste, creating hard, dry fecal material.

Dehydration is often caused by another underlying medical condition such as kidney disease or diabetes mellitus.

Cats that spend a lot of time grooming, especially long haired cats, may develop hairballs. The hairballs may be vomited or pass through the intestines into the colon where they mix with stool and lead to problems with defecation.

Cat constipation can also be due to a mechanical obstruction in the lower GI tract. Fractures in the pelvis can compress the colon making passage of fecal material difficult. Polyps or masses in the colon can also lead to a partial or full obstruction in the colon.

Complications of Chronic Constipation

Chronic constipation can be a very serious medical condition. When a cat is not able to pass stool at all, the term obstipation is used.

Obstipation can lead to absorption of bacterial toxins from the stool into the blood stream, causing endotoxemia. Endotoxemia causes lethargy, anorexia, and in severe cases, organ damage which can be life threatening.

Chronic constipation and obstipation can also cause irreversible damage to the muscles and nerves in the colon. Over time, megacolon may develop.

Megacolon is a serious problem in which the colon is dilated and unable to contract to expel fecal material. In severe cases, the colon may need to be removed.

What Is Metamucil?

Metamucil is the brand name of a fiber supplement that contains psyllium husk. Psyllium is passed through the digestive system and absorbs water.

It increases fecal mass, softens the stools, and stimulates contractions in the colon to help push stool out. Metamucil is safe to use in cats and it is readily available over the counter at drug stores, grocery stores, and superstores such as Walmart and Target.

There is an unflavored version that can be mixed with food.

Metamucil Dosage for Cats

Cat in green litter box

Many cats experience recurring episodes of feline idiopathic cystitis. Long-term management can help to prevent these repeated episodes.

The starting dose for cats is ¼ teaspoon once daily for cats under 8 pounds and ¼ teaspoon twice daily for cats eight pounds and over.

If you don’t notice an improvement, you can increase the dose by 1/8 -1/4 teaspoon.

You should see an improvement in the stools within a few days if it is going to be effective. Metamucil is very safe in cats. If too much is given, cats may experience abdominal pain and/or diarrhea.

View on Walmart

If you see these signs developing, reduce the dose or discontinue completely. Psyllium is also available in a capsule form.

The capsules may contain 500mg or 1000mg, so make sure you read the bottle carefully. The average cat over 8 pounds should receive 500mg per day. You can either give the capsule whole or open the capsule and mix it with food.

Alternatively, you may use a syringe to gather a small amount of watered-down food mixed with an appropriate dose of Metamucil and carefully syringe it into your cat’s cheek pocket.

Cats under 8 pounds should receive 250mg psyllium per day. Since it is not available in this strength, you can open the capsule and mix approximately ½ of the powder in the capsule with food.

Is Metamucil Safe for Long-Term Use?

Fiber supplements such as psyllium and Metamucil don’t work for every cat and are not recommended for long term use. The increased bulk of the stool can lead to dehydration and can worsen constipation with time. Cats with chronic constipation usually have an underlying medical cause.

Possible medical causes include chronic kidney disease causing dehydration which leads to constipation, compression of the colon from other internal factors such as an enlarged bladder or prostate, enlarged lymph nodes, or trauma to the pelvic canal, a growth in the colon, or megacolon – a condition in which the colon no longer contracts to push stool out.

In all of these cases, long term use of fiber additives will make the condition worse.

Alternatives to Metamucil for Cats

Alternatives to Metamucil for Cats

Metamucil is not the only dietary fiber additive or constipation treatment that is safe for cats.

MiraLAX is a good over-the-counter alternative to Metamucil or psyllium. The active ingredient in MiraLAX is polyethylene glycol 3350.

I know polyethylene glycol sounds scary, but it is a very safe product and is not readily absorbed into the bloodstream.

MiraLAX works as an osmotic diuretic, meaning it pulls fluid into the stool to soften it. There is a wide dose range – I usually recommend starting with 1/8 teaspoon twice daily and gradually increasing it if needed with a maximum dose of 1 teaspoon twice daily.

Also Read: Cat Stool Chart: Decoding Your Cat’s Stool

If the dose is too high, your cat may develop diarrhea, nausea, or abdominal pain. MiraLAX comes either in an orange flavor or as a tasteless powder and can be mixed with your cat’s food for easy administration.

You can also mix it in water and syringe it into your cat’s mouth. MiraLAX should have a laxative effect within one to three days.

If you have tried the over-the-counter remedies and your cat is still only passing small, dry, hard feces, a trip to your veterinarian is in order.

Home Remedies for Constipation

The first thing to try to help your constipated cat is to increase his water intake. A lot of cats don’t like drinking out of small bowls. Use a larger bowl so that the whiskers don’t touch the edge of the bowl. Other cats prefer running water.

Some cat owners will run the tap a few times a day to allow their kitty to drink. Kitty water fountains are also available so that your cat always has a source of running water. Regular cleaning of water fountains are important to prevent mold and algae.

A high-fiber diet can also help with constipation. A spoonful of canned pumpkin once a day is a good source of fiber.

You may also be able to find good quality over-the-counter high-fiber diet. Commercially available hairball diets tend to have a higher fiber content and may be beneficial to help with constipation.

Veterinary Treatment of Constipation in Cats

Your vet may recommend abdominal x-rays to see how much stool is in the colon, determine if the colon is dilated (as in the case of megacolon) or if there is a physical obstruction causing constipation.

She may recommend blood tests to determine if there is an underlying cause of dehydration, such as kidney disease. She may recommend fluids to help rehydrate your cat and may possibly give a warm water enema. (Please note, I do not advise giving your cat an enema at home.

Certain enemas contain phosphate which can kill cats and if an enema is not done appropriately, tears in the colon can occur.

Your veterinarian may prescribe lactulose. Lactulose is a sweet liquid that increases the amount of water in feces so that it doesn’t become firm and dry.


Fiber supplements, such as Metamucil, are safe and easy to find. They can help relieve minor episodes of constipation in most cats.

Don’t forget to make sure your cat is drinking enough water to prevent dehydration and contact your veterinarian if the condition does not improve within a few days.

Frequently Asked Questions

How much Metamucil can I give my cat for constipation?

If your cat is under 8 pounds, start with ¼ teaspoon once a day. If your cat is over 8 pounds, give ¼ teaspoon twice a day. Look for unflavored powder and mix with canned food. Cats eight pounds and over can receive 500mg per day.

Cats under eight pounds can receive 250mg per day. Psyllium is usually available in 500mg and 1000mg capsules. I recommend to find the 500mg capsules. Open the capsules and mix the powder in the capsule with canned food.

With smaller cats (under eight pounds) use your best judgment to mix in approximately ½ of a 500mg capsule with food.

What can you give your cat for constipation?

If your cat is constipated, the most important thing is to increase his or her water intake. Make sure there is fresh water and your cat is drinking it. Feed canned food, which has a higher content than dry food.

You can also try over-the-counter treatments for humans, such as Metamucil, psyllium, or MiraLAX. Do not use stimulant laxatives, such as Bisacodyl, Senna, or Castor oil in a cat. If you are unsure if a product can be safely given, call your veterinarian.

What is good fiber for cats?

If you want to increase the fiber content for your cat, I recommend to start with the food. Over the counter weight loss foods tend to have higher fiber contents. There are also many prescription foods available through your veterinarian that have a higher fiber content.

If you want to add fiber to treat constipation, Metamucil or psyllium can be used short term. Long term use of these supplements is not recommended as they can cause dehydration and make constipation worse over time.

Will Metamucil hurt cats?

Metamucil is safe to use as a short term solution for constipation. Metamucil increases the bulk of the stool in the colon. Over time, this can lead to dehydration and can worsen constipation. If you do not see an improvement in your cat's litter box habits after one to two weeks of Metamucil, contact your veterinarian.

Will Metamucil help my cat to poop?

Metamucil is a fiber supplement. Fiber increases the fecal mass, softens the stools, and stimulates contractions in the colon to help push stool out. If your cat has mild constipation, Metamucil should help. However, if your cat is still not able to poop after a few days of treatment with Metamucil, contact your veterinarian. Your cat could have an obstruction or blockage preventing him from passing stool.

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About Jennifer Shepherd, DVM

Jennifer Shepherd received her doctorate of veterinary medicine from Colorado State University in 2000. She completed a small animal medicine and surgery internship at the Ontario Veterinary College before entering private practice Dr. Shepherd owns Cloquet Animal Hospital in Northern Minnesota where she practices full time. In her free time she enjoys writing, photography, running and spending time with her husband, three children, two dogs, and one spoiled cat. She is pictured here with her best running dog Apollo, a Portuguese Water Dog who can’t swim but loves playing in snow.

7 thoughts on “Metamucil for Cats: What You Need To Know”

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    1. small mallory photoMallory Crusta

      Hi Robert, I’d recommend talking with a vet, but it really depends on the nutrient content of your cat’s existing food. If it’s already a high-fiber product, you could end up giving too much and having problems as a result. Again, the answer will be affected by your cat’s unique situation.

  1. Jim Cardin

    My cat is female. She use to urinate a healthy stream, now all she can do is dribble very small amounts. she is now 17and 1/2 years old. She no longer uses the litter pan all the time. Please help.

    1. small mallory photoMallory Crusta

      It’s not ideal, but it should be okay. The sugar and artificial sweeteners in these formulas aren’t ideal, but there’s nothing in them that would be toxic.

  2. Anton Neumann

    I was surprised about your comments in regard to giving a cat psyllium long term. We have 3 cats. Our mother cat (now 19) almost died from megacolon and had to have an operation. After the operation she again got constipated and we thought we would lose her. We have been giving her psyllium ever since (May 2020) together with home cooked food as well as prescription food. She has been fine. As her two kitties (now 13) had small hard stool we thought it a good idea to give them psyllium in the hope that we would avoid them getting megacolon later on. They too seem fine. We go to our vet regularly so I’ll mention that all three are on long term psyllium but up to now our sense is that it’s keeping our 19 year old (megacolon) cat alive and preventing hard stools in the other two.