Cat constipation: causes, home care and when it's an emergency

Cat constipation is common, and most mild cases are easy to treat. The first job is to be sure your cat is straining to poop and not to pee, because the two look alike and one of them can kill a cat within a day or two. If you’re not sure how quickly to act, our should I go to the vet check can help.

Is my cat straining to poop or straining to pee?

International Cat Care notes that it can be hard to tell whether a cat is straining to urinate or to pass feces, and that struggling to pass urine can be an emergency. Both make a cat go in and out of the litter box, squat for a long time and sometimes cry.

A urinary blockage stops urine leaving the body. Cornell Feline Health Center describes it as an absolute emergency: the cat passes little or no urine and becomes more and more distressed. Toxins and potassium build up in the blood, and the cat’s condition can get worse fast. Male cats are at higher risk because their urethra is longer and narrower.

Check the litter box. Normal-sized urine clumps mean the bladder is emptying. No clumps, or only tiny ones, in a cat that keeps straining means you should go to a vet now. If you can’t tell, treat it as urinary until a vet says otherwise. Read more about urinary blockage in male cats.

What are the signs of cat constipation?

According to International Cat Care and VCA Animal Hospitals, signs include:

• Straining or taking a long time to pass stool
• Digging around and spending extra time in the litter box
• Crying out or seeming in pain while passing stool
• Pooping less often than usual
• Small, hard, dry stools
• Pooping outside the box

Some constipated cats pass a little liquid stool or mucus. This can look like diarrhea, but VCA explains it is often fluid squeezing around a hard mass. Cats with severe constipation may also lose their appetite, vomit and become lethargic.

Most cats poop about once a day. VCA advises calling your vet if your cat hasn’t pooped within 48 to 72 hours of the last bowel movement. Our cat poop checker can help you describe what you’re seeing to your vet.

What causes constipation in cats?

When stool stays in the colon too long, the colon keeps drawing water out of it. The stool gets drier and harder, which makes it even harder to pass. Common causes include:

Merck Veterinary Manual lists older, overweight cats, cats with chronic kidney disease and cats that have been constipated before as being at higher risk. If your older cat is also drinking and peeing more, read our guide to cat kidney disease. If they’ve slowed down on stairs or jumps, arthritis in cats may be making the litter box hard to use. Long-haired cats that swallow a lot of fur may also benefit from our guide to hairballs.

What is megacolon in cats?

Megacolon means a very enlarged colon that no longer contracts properly. VCA calls it the most common cause of constipation in cats. It can be a problem in its own right, with no known cause (idiopathic megacolon). It can also develop after repeated bouts of constipation and obstipation, which is severe constipation where a hard mass of stool can’t be passed at all.

That’s why Cornell recommends treating constipation fairly aggressively, so it doesn’t progress. Many cats with megacolon can be managed with diet and medicines. When they can’t, a vet may suggest surgery to remove most of the colon, called a subtotal colectomy. International Cat Care notes that after an initial period of diarrhea, long-term results are generally very good.

When should I take my constipated cat to the vet?

Call your vet and book a visit if:

• Your cat hasn’t pooped in 48 to 72 hours
• They strain with little or nothing coming out
• They seem uncomfortable, or constipation keeps coming back
• They have ongoing constipation along with weight loss, thirst or reduced appetite

Go now for any sign in the red box at the top, or to an emergency vet if your clinic is closed.

A vet will feel your cat’s belly and may do a rectal exam and x-rays to see how much stool is in the colon and whether anything is blocking it. Blood and urine tests look for dehydration, kidney disease and other causes. Mild cases are often treated with fluids, a prescribed laxative and a diet change. Severe cases may need a hospital stay, fluids through a drip and removal of the hard stool under anesthesia.

How can I help a constipated cat at home?

These are the kinds of changes vets recommend, often after an exam to rule out a blockage. Ask your vet which suit your cat.

• More water. Water intake is the foundation. Offer fresh water in several places, try a water fountain and add a little water to meals. Our cat water intake calculator shows roughly how much your cat needs.
• Wet food. International Cat Care recommends feeding wet food rather than dry to keep up fluid intake.
• Fiber. Merck lists psyllium, wheat bran and plain canned pumpkin mixed into canned food as fiber options for mild constipation. Your vet can tell you how much, or suggest a high-fiber prescription diet. Merck also advises that a cat should be well hydrated before starting extra fiber, to avoid making an impaction worse.
• A better litter box. Keep boxes clean, add more boxes in a multi-cat home and put them in quiet places. For stiff or older cats, International Cat Care suggests a low-sided box with soft, sandy litter.
• Treat pain. If arthritis makes squatting painful, pain relief prescribed by your vet can help your cat use the box normally.
• Regular grooming. Brushing long-haired cats reduces the amount of fur they swallow.

Track when your cat poops and what it looks like. A note such as “one small hard stool in three days” tells your vet far more than “a bit blocked up.”

Why shouldn’t I give my cat human laxatives or an enema?

It’s tempting to reach for something from the pharmacy. Don’t. Merck Veterinary Manual warns that laxatives made for people can be very dangerous for pets, so only give the one your vet prescribes. Other risks:

• Enemas. Merck states that phosphate-containing enemas must be avoided in cats because they can cause severe, life-threatening electrolyte imbalances. Cornell notes that some cats need sedation for an enema. Only give one at home if your vet has shown you how and supplied the product.
• Mineral oil by mouth. Merck advises using mineral oil only rectally, because a cat can inhale it when it’s given by mouth and develop aspiration pneumonia.
• Laxatives in a dehydrated cat. Merck notes laxatives can make dehydration worse, which is one more reason to have your vet check your cat first.
• Home remedies. Don’t try to remove stool from your cat’s bottom yourself. A cat that can’t pass stool needs a vet.

Your vet will choose the right product and set the dose for your cat. If constipation keeps coming back, ask about long-term options such as a prescription diet or a medicine that helps the colon contract. For other digestive signs, see our guides to cat diarrhea and cat vomiting.

Written by the CatsMed Team from the sources above. This guide isn’t reviewed by a veterinarian and isn’t a substitute for one. See how we research.