Why Does My Cat’s Poop Smell So Bad?

Cats use their urine (pee) and feces (poop) to mark their territory. Their ancestors either buried the poop to hide from predators or didn’t bury the poop to ensure their territory was well marked—and stinky. 

While pet parents love their cats dearly, this habit of allowing everyone to get a whiff of cat poop is not preferable. And if your cat’s poop is particularly stinky, it can be unbearable! You might be wondering: “Why does my cat’s poop smell so bad?”

Here we cover what cat poop should be like, and what could be causing particularly foul litter box odors.

Healthy Cat Poop: What Does it Smell Like?

Healthy cat poop does have a smell, and it doesn’t smell great, but it shouldn’t stink up your whole house. The wafting smell typically decreases after a few minutes. 

Healthy cat poop should be formed in logs 1 inch or longer that stay formed when picked up. The poop may leave a light amount of residue on the litter scoop but shouldn’t look wet or stick to the scoop. 

Healthy, low-stress cats also get their poop into the litter box.

Terrible Cat Poop Smell: Getting a Whiff

While we can all agree that cat poop doesn’t smell good, it shouldn’t smell like rotten eggs, death, iron (metallic), or be so potent that you cannot stand to be in the room. A lot of times, foul smelling cat poop can be detected from anywhere in the house—at least on the same level. 

The smell lingers until it is scooped and cleaned up. If your cat did not cover the poop with litter (or it’s not in the litter box), this will be especially stinky! If your cat’s poop is this foul, it’s likely her farts are pretty bad, too.

Cats are fastidious groomers—they clean themselves immediately if dirty. If they are not grooming poop off themselves, something is wrong. Your cat should definitely not smell like poop.

Why Does My Cat’s Poop Smell So Bad?

There are some reasons your cat’s poop may smell abnormally bad:

Diet. If your cat’s diet is not well-balanced or it is hard to digest, she may have foul smelling poop.

Inflammatory bowel disease. This is often caused by allergies to food. The most common allergies are to beef, fish, and chicken [1]. Sometimes cats have inflammation in their guts without an allergy which would also cause foul poop.

Parasites. There are many parasites common to kittens and adult cats that live outside, including roundworms and coccidia. The parasites that tend to upset a cat’s gut the most are Giardia spp. and Tritrichomonas spp. Special testing and long courses of treatment are required to get rid of these parasites.

Liver or gallbladder disease. The liver is a part of the digestive system, creating bile and nutrients as well as filtering toxins. The gallbladder is essential to aiding digestion of fat in foods. Liver disease or gallbladder disease can cause a cat’s poop to smell bad.

Pancreatic disease. The pancreas is a part of the digestive system, providing enzymes needed to break down food and get nutrients. Some cats experience pancreatitis, or an inflamed pancreas, that can last a long time. In rare cases, a cat may lose so much pancreas to scarring that it doesn’t function at all.

Medications. Some medications, like antibiotics, will disrupt normal gut bacteria. When normal bacteria are killed, abnormal bacteria take over and affect gut health in cats. This can lead to stinky cat poop. 

Stress. Stress can cause gut upset due to hormones that change when a cat is stressed. Whether it is a one-time event (like a move to a new home) or chronic stress (like being picked on by another cat), stress can change a cat’s gut health.

Any other illness. Cats with any disease become stressed due to pain or discomfort. Even though some illnesses are not related directly to cat gut health, being sick in general can affect the gut.

How to Stop Your Cat’s Poop from Smelling Really Bad

The first thing to do would be to discuss the issue with your veterinarian. Your vet will need to run some quick tests and examine your cat to ensure she doesn’t have parasites or other illnesses that show up on bloodwork. Inflammatory bowel disease is a common issue in cats and requires a surgical biopsy to definitively diagnose it. If your veterinarian suspects IBD, they will likely start with medications or a special diet to help with symptoms before doing a biopsy.

Here are some common ways that veterinarians recommend treating cat poop that smells bad:

Diet Change 

If your cat has diarrhea (stool that is not well formed) or your cat is constipated (strains to poop and it takes at least 2 days to poop), a high-fiber diet may be best for your cat. These diets are meant to increase multiple kinds of fiber in the food and are super digestible, meaning it is easy for the guts to break down the food. 

On the other hand, the best choice for your cat could be a novel protein (a new protein source they’ve never eaten before) or hypoallergenic diet (where a protein source is broken down to the point where the body does not recognize it). These diets are intended to avoid food allergies and provide high-quality nutrition. Results may not be seen for up to two months, and these diets must be the only thing fed—no treats and no other foods.

Probiotics

Probiotics contain live bacteria that survive and thrive inside a cat’s acidic stomach. These “good” bacteria can do wonders for balancing the gut and aiding in better digestion.

Medications

If your cat is diagnosed with an illness, they may require medications either short-term or long-term. Sometimes cats with diarrhea will be given medication like metronidazole (an antibiotic with anti-inflammatory properties that can help with an upset GI tract) or a steroid (which can help with inflammation of the GI tract and immune system response).

Decrease Stress 

If your cat is experiencing stress in the home, work on decreasing those stressful situations. For example, if you have more than one cat and there is aggression between them, separating them at certain times and giving medications to both may be useful. Increase enrichment for your cat by providing new toys, puzzle feeders, places to climb, and things to scratch. Try cat pheromones in stressful zones of the home. Medications or natural supplements such as hydrolyzed milk protein may help as well.

Homeopathic Remedies 

Cats can benefit from an increase in fiber in their food. The best way to do this is to add psyllium powder. A good dose is ¼ teaspoon per meal. With cats experiencing diarrhea, plain cooked chicken (without skin or bones) can be fed to your cat for less than 1 week. This may help by decreasing carbohydrates, which are harder to digest when the guts are inflamed. (Keep in mind that this is NOT balanced and feeding for more than a week is detrimental to your cat.)

How to Get Rid of Cat Poop Smell

If you are looking to get rid of that stinky cat poop smell, here are some tips to beat unpleasant odors:

Always keep the litter box clean. Allowing cat poop to linger in the box will increase the smell of your home. Scoop the litter box at least once per day, and twice daily if possible (or whenever the poop is present!). Completely empty the litter box and clean the box with dish soap and water at least monthly, but more frequently if able. 

Make sure you have enough litter boxes. Each cat in your house should have 1 litter box, and it’s recommended to add one additional one. So, if you have 2 cats, you should have 3 litter boxes. Place them in different locations (and on different levels) in your home.

Consider switching cat litter. If your cat is not burying her poop, she probably doesn’t like the type of litter you have bought. If you are using a pelleted litter, try a softer clay litter. Clay litter is easier to bury poop and thus better masks the smell. Make sure the litter is 2-3 inches deep as well.

Use cat-safe air fresheners. The use of odor-absorbing air fresheners is a great way to contain smells before you can get to cleaning the litter box. Place one near each litter box. Just make sure the air freshener is completely contained in a container that cannot be accessed by your cat. Avoid sprays and air fresheners that mask instead of absorb smells, as these can be harmful or—at the very least—annoying to your cat.

Clean accidents quickly. If your cat poops outside of the litter box, immediately clean it up with a gentle cleanser. Avoid any cleaners with phenols or pine oil, as these are toxic to cats. If your cat pooped on a carpet, choose an enzymatic cleaner specially designed for pet odors.

Stinky Cat Poop: When to See a Veterinarian 

Call your veterinarian if you notice that your cat’s appetite or activity has decreased. If your cat has diarrhea for more than 3 days, it contains blood or mucus, or it is severe and/or frequent, dehydration is likely and veterinary care is needed. Any vomiting, apparent weight loss, or changes in behavior associated with feeling ill should be addressed right away.

If your attempts at home have not resolved the foul smells in a month, you should call your veterinarian. Sometimes bad-smelling cat poop is a symptom of something more serious and should be investigated.

Cat poop that smells really bad is not an emergency. However, if you notice your cat having no appetite, being very lethargic (not wanting to move much), or vomiting multiple times over 24-48 hours, you should seek emergency care for your cat.