# Diabetes in Cats: Diarrhea, Vomiting, and Other Gut Signs Diarrhea in cats with diabetes is common and usually has more than one cause. Poorly controlled blood sugar, a recent diet change, pancreatitis, or a separate gut problem can all trigger loose stools and vomiting. This article explains what those gut signs mean and when vomiting signals a medical emergency. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Gut signs are the rule, not the exception. In one study of diabetic cats with no prior digestive disease, 83% of owners reported at least one gastrointestinal problem [1]. - Vomiting that comes with not eating, weakness, or fast breathing can mean diabetic ketoacidosis, which is an emergency. Go to a vet now. - Never stop or change insulin on your own because your cat is vomiting or having diarrhea. Call your veterinarian first. - Diet changes are a common trigger for loose stools in diabetic cats, so any switch should be made slowly and with your vet's guidance. - Bring your cat in for a routine visit if gut signs last more than 24 to 48 hours, even if your cat seems otherwise fine. ## What Diabetes Means in Plain Words Diabetes mellitus is a chronic disorder of carbohydrate metabolism caused by a relative or absolute lack of insulin [2]. Insulin moves sugar from the bloodstream into the cells that need it. When insulin is missing or the body stops responding to it, sugar builds up in the blood while the cells starve [3]. Cats most often develop the Type II form, where the body's cells do not respond appropriately to insulin [3]. Type I, where insulin production drops, is less common in cats. Either way, the result is high blood sugar and sugar spilling into the urine. Diabetes is common. Estimates suggest between 1 in 100 and 1 in 500 cats will be diagnosed during their lifetime [3]. Most cases appear in middle-aged to older cats [2]. ## Gut Signs Owners Notice in Diabetic Cats The classic diabetes signs are increased thirst, increased urination, increased appetite, and weight loss [2]. Gut signs often show up alongside them, and sometimes they are what pushes an owner to call the vet. ### Diarrhea and Loose Stool Diarrhea in cats with diabetes can range from soft stool to watery, frequent episodes. In the study of diabetic cats, all of them had increased wall thickness in the stomach, duodenum, and jejunum on ultrasound, even though the ileum and colon looked normal [1]. That means the upper gut is often quietly inflamed in diabetic cats, whether or not owners see obvious signs. ### Vomiting A cat throwing up with diabetes may be dealing with several things at once. Chronic high blood sugar can slow stomach emptying and change gut motility. Pancreatitis, which is common in diabetic cats, causes vomiting and appetite loss. A sudden switch to a new diabetic diet can also upset the stomach. ### Appetite Changes and Weight Loss Some diabetic cats eat ravenously and still lose weight. Others stop eating, which is a bigger concern. A diabetic cat that will not eat cannot safely receive its usual insulin dose in many cases, so this needs a call to your vet the same day. ### Other Signs That Travel With Gut Problems Watch for lethargy, hiding, dehydration, bad breath, or breathing changes. These point toward a more serious problem than simple dietary upset. If your cat has vomiting or diarrhea with blood, treat it as urgent. See [Cat Vomiting and Diarrhea with Blood: Emergency Signs](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-vomiting-diarrhea-blood-emergency). ## Causes and Risk Factors Behind Gut Signs ### Poorly Controlled Diabetes When blood sugar stays high, the whole body feels the effects, including the digestive tract. Gut complications are well documented in diabetic people, affecting up to 75%, and similar problems appear to be common in cats [1]. Good glucose control often improves gut signs. ### Diet Changes Switching to a diabetic-friendly diet is a normal part of treatment, but rapid changes can cause diarrhea. Any new food should be introduced gradually over one to two weeks, mixed with the old food. ### Pancreatitis and Other Gut Disease Pancreatitis is a frequent companion to feline diabetes. If your cat has a painful belly, vomiting, and refuses food, ask your vet about it. You can read more about the signs at [Pancreatitis In Cats Symptoms](/knowledge/veterinary-medicine/symptom-guides/pancreatitis-in-cats-symptoms). ### The Gut Microbiome Diabetic cats have different gut bacteria than lean cats. One study found clear differences in the bacterial communities in the small intestine between lean and diabetic cats, with lower levels of one major bacterial group in diabetics [4]. How much this contributes to diarrhea is still not well established in veterinary research. ### Other Conditions That Complicate Diabetes Some cats have a second disease driving their diabetes. Cushing's syndrome, a hormone disorder, can occur with diabetes and make blood sugar hard to control [5]. In one report, a cat with both conditions was treated with trilostane at 2 mg/kg by mouth twice daily along with insulin glargine at 2 IU per cat under the skin twice daily [5]. Doses like these are set by your veterinarian based on your cat's weight and test results, never by an owner. ### Risk Factors for Diabetes Itself The main risk factors for developing diabetes in cats are obesity, increasing age, physical inactivity, male gender, and use of steroid medications for conditions like asthma [3]. Burmese cats may be at higher risk in some countries, though this may not hold true in the United States [3]. | Gut Sign | Common Cause | Urgency | |---|---|---| | Soft stool, no other signs | Diet change, mild gut upset | Routine visit if it lasts past 48 hours | | Vomiting once or twice, still eating | Diet, mild pancreatitis | Call your vet same day | | Vomiting plus not eating | Pancreatitis, ketoacidosis | Same day, emergency if weak | | Diarrhea with blood | Gut bleeding, severe inflammation | Emergency now | | Vomiting plus fast breathing or collapse | Ketoacidosis | Emergency now | ## How Diabetes and Gut Problems Are Diagnosed Your veterinarian diagnoses diabetes by finding persistently high glucose in both blood and urine along with matching clinical signs [3]. A single high reading is not enough, because stress alone can raise a cat's blood sugar. Measuring fructosamine helps separate stress-related spikes from true diabetes [2]. Your vet will also run tests to rule out other diseases that can cause similar signs, including urinary tract infection, chronic kidney disease, pancreatitis, and hyperthyroidism [3]. If your cat drinks a lot of water, this guide can help you understand why that matters: [How to Tell If Your Cat's Increased Thirst Is a Sign of Kidney Disease or Diabetes](/knowledge/veterinary-medicine/senior-and-chronic-care/cat-increased-thirst-kidney-disease-or-diabetes). For gut signs, your vet may recommend abdominal ultrasound. In diabetic cats, ultrasound commonly shows thickening of the stomach and small intestine walls [1]. Blood work can check for pancreatitis and other organ problems. If your cat has hard-to-control diabetes, testing for Cushing's syndrome may be worthwhile, since it can be underdiagnosed in diabetic cats [5]. ## Treatment Options for Diabetic Cats With Gut Signs Treatment has two tracks: controlling the diabetes and settling the gut. ### Insulin and Glucose Control Insulin injections plus diet changes are the foundation of treatment for both dogs and cats [2]. Cats can sometimes achieve remission, meaning they no longer need insulin, while dogs generally need it for life [2]. Your vet will choose the insulin type and dose based on your cat's weight, test results, and response. Never adjust the dose yourself. ### Diet Your veterinarian will recommend a specific diet and a transition plan. Move slowly. A sudden switch is one of the most common reasons a diabetic cat suddenly has diarrhea. ### Treating the Gut Directly Depending on the cause, your vet may treat pancreatitis, prescribe medications for nausea or gut inflammation, or add probiotics. If a second disease like Cushing's syndrome is present, treating it can improve both the gut signs and the diabetes. In two reported cats with diabetes and Cushing's syndrome, treatment with cabergoline at 10 μg/kg by mouth led to diabetic remission within 1 and 6 months [6]. That is a specific case report, not a standard protocol, and your vet will decide what fits your cat. ### Newer Options The 2026 AAHA diabetes guidelines cover newer treatments including SGLT2 inhibitors, various insulin choices, and at-home glucose monitoring devices [7]. Ask your vet whether any of these fit your cat. ## Recovery, Outlook, and Long-Term Management Most cats can be managed well. Successful control means the cat's clinical signs ease and low blood sugar episodes are avoided, and remission is possible for some cats [7]. The 2025 iCatCare guidelines stress that a team approach, with your veterinary clinic and you working together, gives the best outcomes [8]. Gut signs often improve once blood sugar is under better control. Keep a simple log of stools, vomiting, appetite, water intake, and insulin doses. This record helps your vet spot patterns. Some complications are reversible with good control. In two cats with diabetes that developed heart failure signs, clinical and echocardiographic findings improved once blood sugar was stabilized [9]. One cat's heart changes returned during a period of poor control and improved again after treatment was intensified [9]. This shows how much steady glucose control matters for the whole body, not just the gut. If your cat's vomiting or diarrhea is mild and comes and goes, it may not be an emergency, but it still deserves attention. This guide explains the middle ground: [Cat Vomiting and Diarrhea: When to Worry](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-vomiting-diarrhea-when-to-worry). ## Prevention You cannot prevent every case of diabetes, but you can lower the odds. Keep your cat at a healthy weight, encourage daily play and activity, and talk to your vet about steroid use for other conditions, since steroids are a known risk factor [3]. For cats already diagnosed, prevention focuses on keeping gut signs from getting worse. Stick to the diet plan, do not skip monitoring visits, and call your vet at the first sign of vomiting or appetite loss. Early calls prevent emergencies. ## Limitations and When to Contact a Veterinarian No article can tell you what is wrong with your specific cat. Individual cases need a veterinarian who can examine your cat and run tests. **Go to an emergency clinic now if your cat:** - Vomits repeatedly and cannot keep water down - Breathes fast, breathes hard, or seems weak or wobbly - Collapses or cannot stand - Has severe belly pain when touched - Has vomiting with blood or black, tarry stool **Call your veterinarian the same day if your cat:** - Stops eating - Vomits more than once or twice in a day - Has diarrhea that lasts more than 24 hours - Seems dull, hides, or acts painful - Has a blood glucose reading far outside the usual range **Schedule a routine visit if your cat:** - Has soft stool that comes and goes - Has occasional vomiting but still eats and plays - Has any new gut sign that lasts more than a few days Vomiting in a diabetic cat is the sign that worries veterinarians most, because it can be the first visible clue of ketoacidosis, a dangerous buildup of acids in the blood. Ketoacidosis needs immediate treatment, so do not wait to see if it passes. ## Frequently Asked Questions ### Can cats have diabetes? Yes, diabetes is a common endocrine disease in cats. Most affected cats have the Type II form, and middle-aged to older cats are most often diagnosed [3][2]. ### Why does my diabetic cat have diarrhea? The most common reasons are poorly controlled blood sugar, a recent diet change, pancreatitis, or a separate gut condition. Gut wall thickening is common in diabetic cats even without prior digestive disease [1]. ### Can I skip my cat's insulin if it is vomiting? No, do not skip or change insulin without talking to your veterinarian first. A vomiting cat may need a dose adjustment or a vet visit, and the decision depends on your cat's glucose readings and exam findings. ### Is vomiting always an emergency in a diabetic cat? No, but it should never be ignored. One or two vomits in a cat that still eats and acts normal can wait for a same-day call, while repeated vomiting with weakness or fast breathing is an emergency. ### Will my diabetic cat's gut signs get better? Often yes, once blood sugar is better controlled and any gut or pancreatic problem is treated. Some cats even reach diabetic remission, though this varies by cat and is decided by your veterinarian [7][8]. ## Related Articles - [Cat Vomiting and Diarrhea with Blood: Emergency Signs](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-vomiting-diarrhea-blood-emergency) - [How to Tell If Your Cat's Increased Thirst Is a Sign of Kidney Disease or Diabetes](/knowledge/veterinary-medicine/senior-and-chronic-care/cat-increased-thirst-kidney-disease-or-diabetes) - [Cat Vomiting and Diarrhea: When to Worry](/knowledge/veterinary-medicine/digestive-and-urinary-care/cat-vomiting-diarrhea-when-to-worry) - [How to Tell If Your Cat's Vomiting Is a Sign of Kidney Disease](/knowledge/veterinary-medicine/senior-and-chronic-care/cat-vomiting-kidney-disease-sign) - [Pancreatitis In Cats Symptoms](/knowledge/veterinary-medicine/symptom-guides/pancreatitis-in-cats-symptoms) - [Safe Treats For Diabetic Cats](/knowledge/veterinary-medicine/toxicology-and-food-safety/safe-treats-for-diabetic-cats) ## References 1. [Exploring Gastrointestinal Health in Diabetic Cats: Insights from Owner Surveys, Ultrasound, and Histopathological Analysis](https://pubmed.ncbi.nlm.nih.gov/40559766/). Veterinary sciences, 2025. 2. [Diabetes Mellitus in Dogs and Cats - Endocrine System](https://www.merckvetmanual.com/endocrine-system/the-pancreas/diabetes-mellitus-in-dogs-and-cats). Merck Veterinary Manual. 3. [Feline Diabetes](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-diabetes). Cornell University College of Veterinary Medicine. 4. [Diabetic and overweight cats have altered gut microbial diversity and composition](https://pubmed.ncbi.nlm.nih.gov/42034158/). Veterinary journal (London, England : 1997), 2026. 5. [Cushing's Syndrome associated with diabetes mellitus in a Persian cat: clinical features, diagnosis, and therapeutic management](https://pubmed.ncbi.nlm.nih.gov/42592381/). Brazilian journal of veterinary medicine, 2026. 6. [Pituitary tumour shrinkage and diabetic remission in two cats with Cushing syndrome treated with cabergoline](https://pubmed.ncbi.nlm.nih.gov/42576538/). The Journal of small animal practice, 2026. 7. [2026 AAHA Diabetes Management Guidelines for Cats](https://pubmed.ncbi.nlm.nih.gov/42014100/). Journal of the American Animal Hospital Association, 2026. 8. [iCatCare 2025 consensus guidelines on the diagnosis and management of diabetes mellitus in cats](https://pubmed.ncbi.nlm.nih.gov/41224734/). Journal of feline medicine and surgery, 2025. 9. [Reversible congestive heart failure associated with diabetes mellitus in two cats](https://pubmed.ncbi.nlm.nih.gov/42211181/). JFMS open reports, 2026. ## Further Reading - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners) - [Cornell Feline Health Center: Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)