Green Cat Poop: What to Do if Your Cat’s Stool Turns Green

It’s not entirely unusual for our cat’s stool to change in color and appearance from time to time, but what about when it goes from being a normal brown to a noticeable green? Well, this can sometimes be a cause for concern and a reason to take your cat to the vet.

In this article, our doctors will explain what your cat’s green poop means and what you can do about it.

When is your cat’s green poop a cause for concern?

If your cat has been eating a consistent diet for years without issue and suddenly has green poop, you should start to wonder if there is something going on, such as an underlying hepatobiliary issue or parasite.

This is especially true if their poop begins changing to an abnormal consistency as well.  Cat feces that are green can come in a variety of consistencies, smells and shades of color. What details should you be looking for?

Any of the below changes in your cat’s poop should be a cause for concern:

  • Abnormal stool colors can range from a pale green or yellow to a greenish brown.
  • Soft stools that are still partially formed but not a normal, firm consistency.
  • Diarrhea ranging from a cow pie consistency to entirely liquid.
  • Mucousy stools, or fecal matter that is greasy, slippery or slimy looking.
  • Green poop with bright red blood.

If they have diarrhea for 3 or more days it can lead to potentially life threatening dehydration.

However, it is extremely important to understand what your individual cat’s “normal” stool is. If your cat is on a high fiber diet or eats a large amount of grass or vegetables, then they can have stools that naturally appear yellow or green in color.

5 most frequent reasons causing cat poop to turn green

Now that we’ve gone over the ways that green stool can appear, consistency and color wise, let’s talk about the most likely reasons for these changes in your cat’s poop.

#1 Your Cat’s Diet

The food that your cat eats will have a very large influence on the overall appearance of their poop. Sometimes, a sudden change to green can indicate that your cat has been eating grass or even vegetables that have a large amount of chlorophyll in them.

Chlorophyll is the pigment that makes many different plants and foods green. It is found in commonly eaten vegetables like spinach, broccoli, collard greens and asparagus.

A very pale green to yellow color is commonly seen in the stools of cats that are on a high fiber diet.

#2 Parasitic or Bacterial Infections

Protozoan parasites, such as Coccidia (Coccidiosis) and Giardia (Giardiasis), are common causes of a cat’s feces to be green. These stools will often have mucous present or even have a slimy or slippery appearance with an abnormal consistency or consistent, watery diarrhea for several days. Some cats may also experience vomiting, weight loss and fever.

Salmonella can be a cause of green stools as well. This bacteria can wreak havoc on a cat’s digestive tract, causing severe diarrhea and green poop.

#3 A Medication Your Cat Takes

Medications, whether they are vitamins, antibiotics or any kind of synthetic drug, can cause a change in the color and appearance of your cat’s fecal matter. Many common and otherwise normal prescription meds such as anti-inflammatory drugs or even antibiotics have been known to turn cat poop green, so be sure to give your veterinarian a call if this is noticed in your pet.

If your cat has recently been given a dewormer, you may notice your cat’s brown stool shift to green for a short amount of time.

#4 Hepatic Or Biliary Issues In Your Cat

Stomach acid, or bile, is typically a yellow or yellow green color. In a normal gut, the bile is slowly absorbed and deteriorates as the food is digested and stool is formed. When there is an underlying liver and biliary issue, the bile doesn’t have enough time to deteriorate during the digestive process, leading to green stool that is often a soft or diarrhea consistency.

Because of this dysfunction in the digestive tract, there is a lack of proper digestion and absorption of nutrients. This will eventually lead to changes in their physical appearance as well, such as dull hair coat, weight loss, change in appetite, vomiting, yellowing skin (jaundice) and pale or green stools.

Sometimes a dysfunction with the pancreas can lead to green poop in cats. If your veterinarian performs blood work and there is an abnormality with their liver, gallbladder or pancreatic enzymes, this can also be a leading cause of green or even yellow stools.

#5 Your Cat Has Digestive Issues

Cats that have a known inflammatory bowel condition can be prone to bouts of small intestinal diarrhea, which is another common cause of green poop. These felines will often show their frustration with their tummy problems by defecating in places that they shouldn’t or normally wouldn’t.

It helps to have a proper diagnosis by a veterinarian before assuming that your cat has an inflammatory bowel condition. If necessary, your cat should be placed on a special diet to help combat their gastrointestinal issues.

When is green cat poop not a concern?

If your cat has been helping themselves to some grass outside or a serving of a leafy green vegetable, then you probably shouldn’t be overly concerned about green poop for a day or two, but no longer. If the stool persists and leads to bouts of diarrhea or vomiting, then you should contact your veterinarian for further instruction.

What should you do if your cat’s poop suddenly turned green?

Green cat poop can indicate underlying gastrointestinal issues that should be addressed by a veterinarian. However, if you know that your cat has been helping themselves to too much cat grass or you’ve added some veggies to their diet, then you should consider either waiting it out or discontinuing access to these items in the future.

Green cat poop is never really normal, so anytime this happens you could consider calling your cat’s veterinarian.

Is green cat poop ever an emergency?

In most cases, green cat poop is not an emergency. But there are always exceptions depending on the clinical signs that you are seeing at home. If your cat is having a sudden onset of green diarrhea that is happening often, they can become quickly dehydrated, requiring fluids to replace what they lost.

What does normal cat poop look like?

Normal cat poop should be firm, brown and cylindrical in shape.

3 tips for gastrointestinal health in cats

Your cat is bound to have one incident of abnormal stools in their life, but there are always ways to try and prevent problems from occurring in the first place. Here are a few tips on how you can keep your kitty’s tummy feeling its best.

  • Have them on a well-balanced and reputable cat food diet. This would include a diet that has appropriate amounts of protein, fat, carbohydrates with essential vitamins, fatty acids and minerals that a cat needs to be nutritionally complete and healthy. Many veterinarians recommend Hills Science Diet, Royal Canin or Purina as the ideal balanced cat food diet.
  • If your cat goes outside you should have them on a regular deworming schedule. Drontal tablets are a cost effective and simple way to deworm your outdoor cat as it takes care of most feline intestinal parasites. It is recommended to give this dewormer every 3-6 months depending on how often they are outside and if they eat rodents or rabbits.
  • Even if you are deworming regularly, have your cat’s poop checked for intestinal parasites by the vet every year.

Conclusion: green cat stools and what it means

Green cat poop is abnormal and can be a cause for concern. Ideally, you can prevent most issues with a good diet and routine exams. However, don’t hesitate to reach out to your veterinarian when you notice something strange in the litter box like stinky green cat poop, in particular if your cat is also showing other signs of illness.