Constipated Cats

March 1, 2011

Figure 1. A normal stool is Type 4; anything below that is moving toward constipation.

A surprising number of cats have problems with constipation (abnormal accumulation of feces and difficulty defecating), and similar but more serious conditions such as obstipation (complete obstruction of the colon by feces) and megacolon (damaged nerves and muscles in the colon causing an inability to defecate). Constipation is uncomfortable, even painful. Constipated cats may defecate (or try to) outside the litterbox, because they associate pain or discomfort with the box itself. Other signs of constipation include irritability, painful abdomen, lethargy, and poor appetite or even loss of appetite.

The colon, the last part of the intestinal tract, is a large muscular structure ending at the rectum.  It contains most of the intestinal bacteria that reside in the gastrointestinal (GI) tract. These bacteria finish up the digestion of protein. By-products of this process include short-chain fatty acids that nourish the cells lining the colon. Some of these lining cells absorb water, while others secrete mucus to lubricate the stool and keep it moving along.

Most cats defecate about once a day. A constipated cat may only defecate every 2 to 4 days, or even less. Usually the stools are hard and dry, because their long stay in the colon allows for absorption of most of their water content. However, occasionally a constipated cat can appear to have diarrhea, because liquid stool is the only thing that can get around the stuck mass of feces.

Causes for pooping problems include neurologic problems, pelvic injury, obstruction (by hair, bones, etc.), pain (especially in the low back), and Inflammatory Bowel Disease (IBD). (See this article for more info on IBD.) A dirty litter box may cause a cat to avoid the box and become constipated by holding the stool too long. Hooded litterboxes are a particular problem because they hold odor in, potentially making the box environment extremely unpleasant for the cat.

In more than 18 years of experience as a feline veterinarian, I have not personally seen constipation problems in cats who do not eat dry food. It’s logical, therefore, to think that diet plays a significant role in development of the problem. (Since I first wrote this article many years ago, I have heard from 3 readers whose cats developed constipation problems even on all-wet-food diets; so, it’s not impossible, but happily it is fairly rare.) Some cats may need more fiber than is present in very low fiber diets such as most canned, raw and homemade diets. You can always add a pinch of fiber (ground flaxseeds and ground chia seeds, aka Salba, are reasonably palatable and work very well).

Indeed, the initial treatment for constipation is usually a change in diet. Historically, these cats have been put on high-fiber dry foods. Fiber modulates intestinal mobility. Depending on the type of fiber and the circumstances, fiber can either speed up or slow down digestion. It’s therefore used for both constipation and diarrhea. Light, senior, and hairball foods all contain increased fiber, and there are also several medical high-fiber diets.

Usually, any diet change helps, at least initially. However, high-fiber foods often seem to lose their effectiveness over time. More fiber, such as canned pumpkin, may be added. Again, sometimes this produces a temporary improvement. Yet most of these cats continue to have problems.

Since fiber encourages water absorption and increases the amount of stool produced (because it is indigestible), many experts have swung the other way and are recommending “low-residue” diets to minimize stool volume. “Low-residue” means that the food is highly digestible and produces minimal waste. Cats digest protein and fat best, but there is controversy about carbohydrates; it is clear that many cats are carb-intolerant. By this theory, the best food would be high fat, high protein, and low fiber, as well as high moisture. One would think that such a food would also be low fiber, but that is not necessarily true. For instance, Eukanuba Low Residue dry food contains 4% fiber, which is fairly high. However, most canned foods fit the bill, as do most homemade diets. However, Eukanuba Low Residue manages to incorporate a large amount of carbohydrate, even in its canned food. Reading the label is an important skill to develop (learn more about it in this article).

Water balance is crucial in constipated kitties. Most vets will give constipated cats subcutaneous (or even intravenous) fluids to boost their hydration.

Treatment for constipation depends on the severity of the problem. For mild cases, occasional enemas may be all they need. For severe blockages, the cat must be anesthetized for manual extraction of the feces (a process my favorite tech graphically but accurately refers to as a “dig-out”).

Once the cat is “cleaned out” by whatever means, it’s wise to take steps to prevent the problem from recurring. Several options are available; an individual cat may need only one of these, while others need several or all of them.

  • Canned, raw, or homemade diet. High-moisture diets keep the cat hydrated, and these diets are far more digestible  and produce far less waste  than dry food. Because canned and homemade diets tend to be extremely low in fiber, addition of a small amount of powdered psyllium (available in bulk at most health food stores) may be helpful.
  • Water Fountain. Many cats will drink much more running water than they will ever take  from a bowl. There are several types of pet fountains, from “cascades” to “waterfalls” to models that could be from Rome! I first noticed that my cats loved to drink from an inexpensive “feng shui” rock fountain from Bed, Bath & Beyond; but it was too hard to take apart and clean as often as was needed. Worse still, it was made of plastic (as most pet fountains are), which can leach chemicals into the water. We recommend the Glacier Point Fountain for Cats.
  • Miralax. Start with 1/8 tsp twice a day in food, and increase as needed up to 1/4 tsp twice a day. Active ingredient polyethylene glycol; not the same as poisonous ethylene glycol; very safe for cats long-term, and more palatable than other products.
  • Lactulose. This is a sugary syrup that holds water in the stool and keeps the stool soft; therefore it’s easier for the cat to pass. Cats are usually not fond of the taste. Fortunately, lactulose now comes in a mild-tasting powder (Kristalose) that can be encapsulated by a compounding pharmacy, or simply added to canned food.
  • Other stool softeners, such as DSS (docusate sodium). Your veterinarian can prescribe these.
  • Vaseline (Petroleum Jelly). The primary ingredient in most over-the-counter hairball remedies  (Laxatone, Kat-a-lax, Petromalt), petroleum jelly (or its close relative, mineral oil) can be given to the cat by mouth. Most cats tolerate it, many cats come to like it, and a few even enjoy it. The Vaseline brand is, according to my cats, the tastiest; but other cats prefer one of the flavored hairball types. Give 1/3 to 1/2 teaspoon per day. It can also be mixed with a small amount of canned food. However, it can interfere with nutrient absorption so giving it on an empty tummy is best. Note that petroleum jelly is a large molecule that is completely inert in the body. It’s the ideal lubricant and “escort” for intestinal contents, because it reaches the colon unchanged. Vegetable or other digestible oils are broken down and absorbed in the small intestine, and cannot lubricate the colon where it’s most needed.
  • Cisapride (Propulsid). This drug was withdrawn from the market for humans because of dangerous side effects, but it is considered safe for cats. Your vet can order it from a compounding pharmacy. It seems to work best in combination with stool softeners. There are similar drugs being developed, but it could be a long time before they’re available.
  • Pediatric glycerin suppositories. Although they may not appreciate having a suppository pushed into their rectums, most cats tolerate it. Your vet can advise you on technique and frequency.
  • Enemas. This is usually done by a vet, but many cat guardians have gotten good at giving enemas at home. Mineral oil, K-Y jelly, soapy water, and plain warm water are all fine; you may have to experiment to see which one works best for your particular cat.
  • Slippery Elm Bark. This powdered herb can be added to canned food (add extra cool water) or made into a syrup. Its mild taste is well tolerated by most cats. See this article for more information. There are many herbal formulas available for people, but many herbs, such as Cascara sagrada, are too harsh for a cat.
  • Resolve pain issues. Sometimes constipation occurs because of low back pain, which makes it uncomfortable for the cat to defecate. Chiropractic and/or acupuncture can be very helpful. See the directory at for a practitioner in your area.
  • Exercise. Staying active helps stimulate the intestines and keep things moving. If your constipated cat is also a couch potato, try Play Therapy.
  • Stress Management. There is always an energetic or emotional component of any chronic disease, and stress plays a significant role in many gastrointestinal conditions. The essence remedy “Happy Tummy” was designed by SpiritEssence to help address the energetic underpinnings of constipation and other GI diseases.
  • Fluid Therapy. Some cats do very well with occasional (daily to weekly) infusions of subcutaneous fluids. Your veterinarian or vet tech can show you how to do this at home. Give fluids whenever you notice your cat’s behavior indicate oncoming constipation.
  • Manual removal of stool. Commonly referred to as a “dig-out,” this is a procedure done under anesthesia for extreme cases that have not responded to other treatments. It is unpleasant for the digger, and likely painful for the cat post-op. Ask your vet to consider providing pain management for a day or two afterward.
  • ** NEW!** PEG 3350 (Colyte®) infusion. This non-surgical procedure is just beginning to be used in clinics. It requires the cat to spend the day at the vet’s receiving an intranasal infusion of liquid Miralax. It does not require anesthesia, but fractious cats  may require sedation; a dose of pain meds may help keep them calm afterwards. It is relatively comfortable for the cat, and in most cases moves the stool out about 12 hours later. If your veterinarian is on VIN (Veterinary Information Network), the link to the protocol can be found here; or if not, please have your vet fill out our contact form (top menu bar) and I will email it back.
  • Surgery. If there is damage to the nerves and muscles of the colon, a “sub-total colectomy” is the last resort. This surgery removes the colon, and joins the small intestine to the rectum. Unless and until the small intestine develops more colon-like functioning, the result is chronic diarrhea. However, the cat will be much more comfortable. The overall success rate of this surgery is over 90%.

If your cat is chronically constipated, the most important thing for you to do is be observant. Look for early signs of constipation; straining, abdominal discomfort, decreasing appetite, etc. Be aware of how often the cat is defecating. (Replace If he does not produce adequate stool for more than 2-3 days, call your vet, or begin home treatments if you have established this routine. Kitty constipation is far easier to treat when it’s caught early; and dietary changes are more likely to be successful. If you wait, treatment will be far more expensive, and there is a greater chance of irreversible colon damage.

PLEASE NOTE: This is our most popular article, and we get a lot of comments and questions about it. There are many valuable experiences reported that could help your cat, so please take a few minutes to look through the comments below!  Questions about individual cats will be deleted without response. The only thing I can tell you is what you’ll see many times in the comments below: “Please contact your veterinarian.” If you are unhappy with your veterinarian’s advice or treatment, please seek a second opinion. Thanks for your cooperation!

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154 Responses to Constipated Cats

  1. alliecat on June 4, 2014 at 11:40 pm

    i usually NEVER register on websites but this info was so helpful. my poor baby hadnt pooped in 4-5 days. i tried the 1/4 teaspoon of miralax mixed in with some probiotic yogurt and when i got home from an 8 hour shift she had pooped and it was a really good bowel movement. so its worth a try and i hope it works for everyones cat as quickly as it worked for mine.

  2. itssjustmonique on February 10, 2014 at 9:40 pm

    Can anyone help me out?

    I’ve been calling and looking around Safeway and London Drugs but they don’t have Miralax. I’m from BC, if that has any relevance. Does anyone know WHERE I can get some Miralax in stores?

    And I was looking on the website just in case I might have to order this online. But which Miralax should I purchase?
    1) 7 dose
    2) 14 dose
    3) 30 does
    4) travel kits (powder)

    I’ve noticed that these are pills, so am I supposed to break open he capsule and put the 1/4th tsp in his food?

    Thank you!!

    • kittymama1913 on March 3, 2014 at 2:58 pm

      Hi, the 7 dose Miralax “bottle” lasts a really long time and it’s a powder, not pills. You definitly don’t want pills. Plus the powder will last longer. Be sure to start with 1/8 tsp or you may cause your cat to have cramps or become bloated. I give my Andyman 1/8 tsp each morning in his food unless he’s becoming “blocked” then I go to 1/8 tsp morning and evening meals. The 1/4 tsp bloated him too much. It has solved all our problems!!! Good Luck . Do you have a Walmart there? They carry it as do most drugstores.

      • PoppyBean on March 16, 2014 at 11:50 am

        Hi, I’m in Canada, too. Miralax is U.S. – it’s called Restoralax in Canada. My (shelter) cat was prescribed this for chronic constipation by the shelter vet in Toronto. Restoralax is available here in grocery stores that have an in-store pharmacy, and in Shoppers Drug Mart (don’t know if B.C. has a Shoppers). Much cheaper in grocery stores. It’s powdered and tasteless, mixes well in canned food. The Princess was sent home on 1/4 tsp twice a day, but I’ve read a starting dose is 1/8 tsp, increasing if needed to 1/4 tsp.

        It’s also available online from …, I believe.

        Restoralax is also used for humans. It’s a very gentle laxative.

    • strawberry on March 17, 2014 at 8:53 am

      I use Lax-a-day which is approved by my veterinarian, and can be picked up in BC. I bought mine at Shoppers Drugmart, and you follow the instructions the same, starting off with 1/8th tsp. I’m not sure if you were able to get the Miralax online, as I found of online pet pharmacies only deliver within the US.

    • craftyruthie on July 3, 2014 at 5:33 pm

      If you can’t find Miralax, “Restoralax” is the same thing in “human” form, found in any drug store. That’s what I use for my cat; it’s cheaper than a prescription, and doesn’t cause the gas, bloating, and cramping that lactulose did. I had to play around with the dosage until my cat was pooping normally (ie, not constipated but not having accidental poops or diarrhea).

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