Old Cat Diarrhea: Causes and Treatments for Diarrhea in Senior Cats

Old Cat Diarrhea: Causes and Treatments for Diarrhea in Senior Cats

Sep 21, 2021
19 min

Diarrhea is a common condition in senior cats. It can be a simple case of gastric disturbance that soon goes away when the culprit has been eliminated from the digestive tract, or it could be an important symptom of an underlying health issue that needs prompt veterinary intervention.


What Causes Diarrhea In Senior Cats?

There are many potential causes of diarrhea in old cats. If your senior cat is passing soft, unformed stools, be sure to keep a close eye on your pet. He may appear active and healthy at first, but when diarrhea doesn’t stop, your pet can be at risk of dehydration and other serious health issues. Being able to understand why a pet has diarrhea can also help cat parents take a proactive approach to their pet’s health by undertaking measures to protect their pets from suffering the same issue again. Here are the top causes of diarrhea in senior cats:


Changes in diet

Cats can develop diarrhea when there is a sudden change in their diet. Thus, it is always recommended by experts that pet owners should observe a transition period when switching diets. The transition period gives enough time for the cat’s system to get used to the new diet and prevent adverse reactions from happening. When introducing a new diet, the magic word is “gradual”. Start by replacing a small portion of your pet’s daily ration with the new pet food. If your cat continues to eat well without any negative reaction, such as digestive upsets, gradually increase the amount of the new pet food each day while also decreasing the old one. Experts generally recommend a transition period of 7-10 days.


Low-quality pet food

When it comes to pet food quality, there are premium formulas and there are the inferior pet food products. Premium pet foods are generally priced higher but you (and your pet!) will certainly get your money’s worth. These products are made by reputable pet food manufacturers that adhere to AAFCO’s guidelines. They have pet nutritionists that formulate rations to ensure that the nutritional needs of pets can be addressed based on their specific life stage, activity level, health status, etc. Premium pet food uses wholesome ingredients, while their generic counterparts have a lot of fillers and artificial additives in their formulas. The use of rendered ingredients, such as animal hooves, skin, eyes, and feathers of birds, remains to be an important concern in low-quality pet food. These are poor quality sources of protein and may not dwell well in the sensitive stomachs of senior pets and can cause diarrhea.

Food allergies and food intolerance

Senior cats can develop an adverse reaction to food in the form of a food allergy or food intolerance. These are two distinct issues in which chronic intermittent diarrhea is an important consequence. A food allergy is a reaction that is mediated by a cat’s immune system in response to an allergen in pet food. There is a need to identify the specific allergen so it can be removed from the cat’s diet. Food allergies are common in cats that have been eating the same kind of protein for a considerable length of time and have been associated with the development of inflammatory processes in the gastrointestinal tract (GIT).


On the other hand, food intolerance is just a local reaction of the GIT to something that the cat has eaten. Vomiting and/or diarrhea may occur but soon resolves when the trigger factor has been eliminated from the GIT.

Lactose intolerance

Most adult cats are lactose-intolerant because their bodies don’t produce enough lactase, an enzyme that is necessary for the proper digestion of lactose, the sugar that is in milk. On the other hand, it’s another story for kittens because their bodies still produce enough quantities of the enzyme, thus they can efficiently digest milk from their mother and utilize the nutrients in their body. A cat that is lactose-intolerant can develop digestive upsets after consuming milk and milk products.


Spoiled food

Cats find garbage and trash bins irresistible especially when it’s filled with discarded food. Eating spoiled food can increase the risks of diarrhea.


There are infections caused by bacteria, viruses, or fungi that can trigger diarrhea in senior pets. The severity generally varies depending on the causative agent, the extent of the problem, and the immunity of the animal. In severe cases, diarrhea in senior cats can be accompanied by vomiting, weight loss, and dehydration. Without prompt medical attention, affected cats can become severely dehydrated which can have fatal consequences.


Internal parasites

Gastrointestinal parasites depend on their hosts for nutrition and sustenance. Diarrhea is a prominent symptom in heavy parasite infestations. Unfortunately, a heavy parasite load can also increase a senior cat’s risk to various health issues. Thus, even when they are already in their senior years, regular deworming is still a must. Some internal parasites, like Toxoplasma, can be transmitted from infected cats to their owners. Other internal parasites of cats include roundworms, giardia, tapeworms, hookworms, coccidia, and whipworms.


Inflammatory bowel disease (IBD)

Inflammatory bowel disease is a general term that is used to refer to inflammatory conditions that affect the organs of the gastrointestinal tract (GIT), such as pancreatitis, gastritis, enteritis, and colitis in cats. These conditions have potential links to serious medical conditions. Affected cats have chronic inflammation in the GIT and diarrhea is a prominent symptom. There are times when chronic diarrhea may subside and recur later down the road. Diarrhea associated with IBD has the potential to develop into something more serious.


Kidney or liver disease

The liver and kidneys play an important role in removing toxins from the body. When there’s something wrong with any of these major organs, diarrhea can be an important symptom.



Cats may develop diarrhea as a side effect to certain medications that they have been given. Veterinarians usually inform the pet owner about any potential side effects that may develop when pets are on certain medications.


Chemicals and toxins

Diarrhea is a prominent symptom in most cases of poisoning. Other symptoms that can be manifested will depend on the type of toxin or chemical that has been ingested.


Is Cat Diarrhea An Emergency?

Diarrhea is a symptom, not a disease; it is an important indication that there is something wrong within the gastrointestinal tract (GIT). Elderly cat diarrhea is characterized by the passage of stools that are loose or unformed. It can occur suddenly and end even without any medication (referred to as “acute”) or it could be diarrhea that lasts for months (chronic). There are cases when a senior cat with diarrhea does not show other symptoms and appears to be active and healthy. But there are also instances when it is accompanied by other symptoms, such as loss of appetite, fever, lethargy, etc. When this happens, it is recommended that you call your veterinarian.


When To Seek Medical Attention?

An episode or two of loose bowel movement is not really something to be worried about especially if your senior cat is not showing any other symptom and appears active and has a good appetite. However, frequent and persistent episodes of diarrhea need to be brought to the attention of your veterinarian as soon as possible. Recurrent diarrhea can have serious effects especially in old cats, kittens, and those that are suffering from concurrent medical conditions and compromised immune systems.


Treatment Of Diarrhea In Senior Cats

The treatment regimen depends to a large extent on the underlying cause and its severity. The primary aim is to stop diarrhea and replenish the body’s fluids and electrolytes to prevent dehydration and other potential complications. There is a need to identify the underlying cause so the appropriate treatment can be given immediately.


When your old cat has been through several bouts of diarrhea in one day, it is always recommended that you call your veterinarian even if your pet appears active and healthy. You may be asked to give certain home remedies if your veterinarian thinks there is no need to bring your pet to the vet clinic. If your vet prescribes a cat diarrhea medication, be sure to follow dosage instructions properly.


Home remedies for senior cat diarrhea

  • Don’t withhold your pet’s food. Just simplify it and avoid giving treats or table scraps.
  • If it’s caused by a sudden switch in your pet’s diet, go back to giving your pet the old diet.
  • Some cats respond positively to a low-fiber diet while some benefit from a fiber supplement, like canned pumpkin.
  • Make sure your cat is drinking well. Cats with diarrhea need to stay well-hydrated to prevent dehydration.
  • You may try to top up your pet’s kibble with some canned pet food to add some moisture in the diet.
  • Ask your veterinarian about giving probiotics to your cat. These supplements are filled with a healthy amount of good bacteria that is necessary for the cat’s GIT.
  • Before giving any anti-diarrheal medications to your pet, always consult your veterinarian.

Here are some recommended products that could help with your pet’s diarrhea

Royal Canin Medium Digestive Care Dog Dry Food 3kg
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Vitakraft Nutri Znack Chicken Digestive Care Cat Treat 40g
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Kala Health Digestix Digestive Enzymes Pet Supplements 45cts
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NHV Multi Essentials Supplement for Pets 100ml
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Dechra Amoxicillin Tablets For Dogs And Cats 200mg (1 Tablet)
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Dechra Doxycycline Non-Flavoured Tablets for Dogs and Cats 50mg (1 Tablet)
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