Cat Diarrhea with Blood: Is it an Emergency? [Vet Advice]

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  • Diarrhea is not an uncommon complaint in cats – but should you be worried if you see some blood? Many conditions can cause diarrhea with blood in cats, some of which can be life-threatening, but the good news is that many of these are treatable. Let’s look at some common causes, other signs to look out for and when you should take your cat to the vet.

    Understanding cat diarrhea with blood

    Diarrhea is less common in cats than in dogs but there are still numerous potential causes. For almost all of these, we can occasionally see some fresh blood in the feces due to inflammation in the gut. To understand what condition might be causing diarrhea with blood, we need a few definitions.

    1. Blood in the upper gastrointestinal tract: the upper gastrointestinal tract (GIT) consists of the stomach and small intestine. If this bleeds, the diarrhea may contain black and tarry partially digested blood. This is called melena (muh-LEE-nuh). Cats with GIT disease may show these symptoms:

    • Weight loss or lack of appettite
    • Production of abnormal feces
    • Vomiting – potentially with blood in it. The picture below shows a pet pad with digested blood from a cat who ate rodent poison

    Pet pad with digested blood from poisoned cat

    2. Blood in the upper gastrointestinal tract: If the lower GIT (the large intestine or colon) bleeds, the blood in the feces is fresh and red. This is called hematochezia (hee-mat-uh-KEE-zee-uh). This is relatively common in cases of colitis, where the large intestine (colon) is inflamed. You might also notice mucus in the feces and your cat trying to defecate more frequently or straining in the litter box.


    mucus in cat stools on sandy ground
    This amount of blood would warrant an urgent vet visit

    When is cat diarrhea with blood an emergency?

    Signs that your cat needs more urgent assessment by a vet include:

    • Profuse watery diarrhea
    • Red-tinged diarrhea containing a significant amount of blood

      bloody diarrhea on floor

    • Weakness or lethargy
    • Vomiting – especially if this contains blood
    • Not eating or eating very little for > 24 hours
    • Persistent diarrhea with blood for > 24 hours

    While cats may occasionally have a few streaks of blood in diarrhea over a couple of days, lethargy, vomiting or larger volumes of blood are particularly concerning. Cats can rapidly become dehydrated and weak, especially if they stop eating – and some of the conditions that cause these symptoms can progress quickly. Urgent treatment in some cases could make the difference between life and death.

    When to visit the vet

    • Mild diarrhea with a tiny amount of fresh blood? If your cat is otherwise young, healthy and well in themselves, you can consider monitoring them for a few days. If the diarrhea persists, worsens or any other symptoms develop you should book an appointment.
    • Is your cat vomiting, refusing to eat or having severe diarrhea? See your vet as soon as possible to check whether they need treatment, as these symptoms can progress rapidly and cause severe illness.
    • Chronic diarrhea with blood? Book in with your vet to discuss the possible causes and make a plan. Sometimes, chronic cases can flare up – if your cat’s condition suddenly becomes much more severe, see your vet as soon as possible.

    Signs of a possible emergency

    • Hemorrhagic diarrhea with a lot of blood
    • Profuse vomiting or vomiting with blood
    • Lethargy – if they’re still interacting with you normally but sleeping more than usual, they may just be feeling a little poorly. If your cat has become very lethargic, however, and you’ve been noticing blood in their feces, this could be a sign of more severe disease like anemia or shock.
    • Any history of possible toxin ingestion

    Diarrhea can also be divided into acute (short duration) diarrhea and longer duration, chronic diarrhea.

    Cats with acute (short duration) diarrhea with blood: when is it an emergency?

    Acute onset diarrhea with blood can be triggered by stress, dietary indiscretion, dietary hypersensitivity, infections, pancreatitis, parasites or other causes. The gut can be a very sensitive organ so there are many more unusual causes of diarrhea! Let’s review a few of the most common causes, including what might count as an emergency.

    1. Stress

    Stress can cause both acute and chronic mild diarrhea in cats. Cats are highly sensitive and things like a house move, cattery visit or noise from building work can trigger diarrhea. This is typically mild, self-limiting colitis, and they should still be well in themselves. As with other forms of colitis, you’ll often notice mucus and possible a little fresh blood in their feces.

    If you notice this for more than a couple of days, or your cat is showing other symptoms, we recommend getting them checked by your vet, but this usually isn’t an emergency. Read more about signs of stress in cats and how to treat this.

    2. Dietary changes

    If you’ve just changed your cat’s diet, they might take a short time to get used to it. We recommend switching diets gradually over a week to minimize any upset stomachs. Typically, this doesn’t cause blood in feces but if you’ve only noticed a tiny streak with some mucus and your cat is otherwise well, it’s worth giving them 1-2 days to see if things settle. If the diarrhea gets worse in this time and you notice more blood, it’s worth seeing a vet.

    3. Dietary indiscretion

    If your cat eats anything that’s fatty, spoiled or otherwise challenging to digest, you may notice some diarrhea over the next couple of days – and again, you might occasionally see a few streaks of fresh blood. This usually settles down quickly, but if things aren’t improving or your cat is showing other symptoms, it’s best to get them checked out to rule out anything more serious.

    In some cases, the things cats eat can be toxic (like sultanas!). Some toxins can cause more severe diarrhea, bleeding, or other complications, so if you suspect your cat might have consumed medications or substances that you aren’t sure are safe for cats, ring your vet for advice – this could be an emergency.

    Cats may also eat objects that can cause obstruction of the gut – in this situation, you typically won’t see a large volume of feces, but they may still have a little diarrhea, potentially with blood. Vomiting is another common symptom. If you suspect your cat has eaten something that could cause an obstruction and they start to show symptoms, this is an emergency –they can rapidly deteriorate and early treatment gives the best outcomes.

    4. Infections

    You might think that cats, as hunters, are unlikely to develop infectious gastroenteritis. Unfortunately, they can still be affected by a range of bacterial and viral infections, including Campylobacter, Salmonella and viruses like Feline Parvovirus and Feline Leukemia Virus. Infections can affect any part of the gut, causing severe diarrhea, potentially with a significant amount of blood. Occasionally, cats can develop a mild case of gastroenteritis and recover on their own. If, however, your cat develops severe diarrhea (especially with blood), the diarrhea persists for more than 1-2 days or your cat is showing any other symptoms like lethargy or inappetence, it’s important to see a vet sooner rather than later.

    Infectious gastroenteritis can rapidly become an emergency by causing dehydration and even shock if left untreated. Treatment is often supportive (e.g. IV fluids, anti-sickness medications), although sometimes antibiotics may be needed. Some of the viruses that cause this type of diarrhea can be particularly serious so your vet may also recommend tests to rule these out.

    5. Parasites

    We all know cats can pick up worms and your vet will usually recommend regular preventative treatments to avoid this. Occasionally, however, we see cats with a severe case of worms or a different type of parasite like Giardia or Tritrichomonas. In these cases, cats often have persistent diarrhea, which can include mucus, melena (black, digested blood) and fresh blood (hematochezia), alongside other symptoms like inappetence, weight loss or anemia.

    If your cat is unwell and you suspect parasites might be the cause, it’s best to discuss treatment with your vet to ensure you’re using a suitable medication. Some parasites, like Giardia, can be harder to treat and require specific products.

    6. Anal gland disease

    Anal gland issues are much more common in dogs – but cats have anal glands too! From infections to impacted anal glands, they can get a variety of conditions that could cause painful defecation, unpleasant odors and fresh blood in their feces. These conditions can be very painful for your cat and need veterinary treatment, so if you notice any of these signs it’s worth getting them checked.

    7. Toxicities

    Various toxins and medications can cause internal bleeding, including into the gut causing hemorrhagic diarrhea. Rat bait is one example which causes bleeding by acting as an anti-coagulant. This often causes severe bleeding and in addition to bloody diarrhea or vomit you might notice pale gums, a bloated abdomen and lethargy. This is a true emergency and urgent treatment can be life-saving.

    Other toxins that can cause diarrhea with blood include non-steroidal anti-inflammatory painkillers (NSAIDs). These can cause gastrointestinal ulceration, so it’s essential to see your vet urgently if you notice black, tarry feces while using them. If your cat has received an overdose of an NSAID, they are at risk for other side effects too.

    Cats with chronic diarrhea with blood: when is it an emergency?

    Chronic diarrhea lasts for more than 2 weeks – so it typically isn’t an emergency. Some cases can go through acute flare-ups that require emergency treatment, however. Many of the conditions discussed above can become chronic: for example, chronic parasitism, some infections, dietary hypersensitivities or repeated dietary indiscretion, or even chronic stress.

    Two conditions that cause chronic diarrhea in cats are Inflammatory Bowel Disease (IBD) and gastrointestinal cancers. While both of these cause chronic symptoms, cats can still become very unwell and present as emergencies as their symptoms progress. If your cat has had symptoms for a while but suddenly deteriorates, this could be an emergency.

    1. Inflammatory Bowel Disease (IBD)

    Inflammatory Bowel Disease occurs when the immune system causes excessive inflammation in the gut. The exact cause of IBD isn’t known, although dietary hypersensitivities play a role in some cats. It’s a relatively common condition, mainly affecting middle aged cats.

    Alongside chronic diarrhea (with or without fresh blood), symptoms can include vomiting, weight loss and reduced appetite. These symptoms often wax and wane in intensity.

    Unfortunately, there is no cure for IBD, but it can often be successfully managed long-term. Initially your cat may need supportive treatment if they are acutely unwell. After diagnosis, treatment involves hypoallergenic diets, B12 supplementation, probiotics, occasionally antibiotics and frequently anti-inflammatory immunosuppressive drugs like corticosteroids. Many cats with IBD live long and happy lives, but management of this condition is important to avoid malnutrition.

    2. Cancer

    Gastrointestinal cancer is unfortunately not an uncommon cause of chronic diarrhea, especially in older patients. The most common type of cancer to affect the gastrointestinal tract is lymphoma. Symptoms include chronic diarrhea, melena (digested black blood) or hematochezia (fresh blood) in the stools, vomiting, altered appetite and weight loss. In some cats, these go unnoticed until they suddenly deteriorate and present as an emergency.

    Sometimes your vet will be able to give a likely diagnosis of cancer based on your cat’s history and a clinical examination, as a mass may be palpable within the abdomen. If a mass is not palpable or a more definitive diagnosis is sought, further tests including abdominal ultrasound and biopsies may be needed.

    Treatment of such cancers can be successful, potentially involving surgery and/or chemotherapy, but the prognosis is guarded and depends on the extent and type of the tumor.

    There are many other potential causes of acute and chronic diarrhea with blood in cats, including liver disease, kidney disease, clotting disorders, ingestion of anticoagulants (like rat poison), pancreatitis and other diseases not discussed here. The causes of diarrhea range from being relatively benign and likely to resolve by themselves (e.g. stress or a diet change) to being possibly life threatening (e.g. cancer or toxicity). It’s therefore essential if your cat is unwell in themselves or having severe or persistent diarrhea (with or without blood) that you see your vet to fully assess your cat’s individual situation.

    Treatment options for emergency cases

    Treatment depends on the severity and duration of the diarrhea as well as various other factors your vet will assess during their examination.

    If a cat is dehydrated and unwell in themselves or has severe symptoms, your vet may recommend hospitalization for monitoring, diagnostics and supportive treatment. This usually includes IV fluids as well as things like anti-sickness medication to promote appetite. Depending on the case, further investigations can include blood tests, abdominal ultrasound or fecal analysis.

    Is there anything I can do at home to help my cat?

    If your cat has had one or two bouts of diarrhea, potentially with a small amount of blood, but is otherwise well in themselves it may be worth monitoring them over 24 hours to see if things settle.

    Steps you can take to help them at home include:

    • Feeding small meals frequently e.g. 6-8 small meals throughout the day
    • Feeding a blander diet than normal e.g. plain cooked chicken breast or white fish. Alternatively, consider a specially formulated sensitivity or gastrointestinal diet designed to be easily digestible for pets with an upset stomach.
    • If your pet will eat it, try to feed wet food and consider adding a small amount of extra water to their meals to keep them hydrated.
    • Make sure they have a clean litter tray nearby to help avoid any accidents!

    If your cat has more chronic diarrhea with some occasional blood, but for any reason you can’t make it to a vet yet, consider adding in probiotics like Purina Fortiflora and making sure your cat is up to date with worming treatments. Alternatively, try transitioning to a reputable hypoallergenic diet (e.g. Hill’s z/d, Royal Canin, Purina) to see if this helps.

    It’s helpful to check your cat’s weight regularly and monitor for other symptoms like weight loss. If you’re going to take your cat to the vet, take a few clear photos of your cat’s diarrhea so they can assess this too.

    Frequently Asked Questions

    Should I be concerned about blood in my cat’s stool?

    The presence of a small amount of fresh blood is not something to panic about – but it should make you consider your cat’s health. If it occurs as a one off or you spot a tiny bit of blood when your cat has diarrhea for a couple of days, it’s probably nothing to worry about. If it’s persistent, present in larger quantities or the diarrhea is more severe then you should see a vet.

    How long does it take for a cat with diarrhea and blood to recover?

    Acute diarrhea usually resolves in a few days, although it can take up to 1-2 weeks for their feces to completely return to normal.

    Because of the potential for serious health issues, we recommend seeing your vet if diarrhea persists for more than 48 hours.

    Can cat diarrhea with blood be transmitted?

    Some causes of diarrhea with blood are transmissible to other cats and even humans. These include bacteria like Salmonella, Campylobacter and E coli as well as parasites like Giardia. It’s important to put in place additional hygiene measures if your pet is ill to limit this possibility and try to clean the litter tray frequently if it’s used by multiple cats.


    ed, Dobson, J.M. and Lascelles, B.D.X. (2003) Manual of Canine and Feline Oncology. Gloucester: British Small Animal Veterinary Association.

    Harvey, A. and Tasker, S. (2013) BSAVA Manual of Feline Practice: A Foundation manual. Quedgeley: British Small Animal Veterinary Association.


    • Dr. Moss, Veterinarian

      Dr. Primrose Moss graduated from the University of Cambridge with a Bachelor's of Veterinary Medicine. She is currently a veterinary surgeon at Avonvale Veterinary Centres in the UK.