Cat with Blood in Stools But No Other Symptoms (Acting Normal)

As a cat owner and a vet it is alarming to notice blood in your cat’s stools and it can leave you puzzled as to the cause, especially if your cat looks otherwise normal. If they are unwell and not eating well, then it can be particularly concerning. Let’s unpack what blood in your cat’s stools may mean and what to do about it.

What is hematochezia in cats (blood in stools)?

The scientific term for blood in stools is hematochezia (hemato=blood, chezia= faeces/stool). Often it can be obvious that your cat has blood in their stools, particularly when it is coupled with diarrhea (runny stools). But in some cases there may just be a small amount of blood at the start or the end of the stool, or the stool may be covered with some blood and mucus.

Cats that do not use a litter tray may have bloody stool for an extended time before you are aware of it. If cats have black, tarry stool then that is also an indication of blood in the stools that originates higher up the gastrointestinal tract. Blood in the litter tray may be present in the urine or may originate from a bloody vaginal discharge, wounds around the anus or anal gland problems.

Blood in your cat’s stools should never be ignored as it can be an indication of a serious medical condition.

What are the causes of hematochezia in cats? (When my cat otherwise appears to act normally)

If your cat appears to be fine and acts normally, the following conditions are the most likely causing your cat’s issues:

1. Parasites

Parasites are the most common causes of blood in cat’s stool if the cat is otherwise looking normal. There are a variety of different parasites that may cause bloody stools and you may need to submit a stool sample to your veterinarian for analysis to correctly diagnose which parasite is playing a role. This is essential to allow the veterinarian to choose the appropriate medication.


illustration showing worms in cat's stomach

Cats may be susceptible to roundworms as well as tapeworms and these can cause bloody stools, particularly in kittens. In most cases, the cat or kitten will look normal and have a normal appetite. They may or may not have diarrhoea and you would often see a small amount of blood on the surface of the stools. Sometimes kittens will also develop a pot-bellied appearance.


Kittens should be dewormed every 2 weeks until they are 12 weeks old. Thereafter all cats should be dewormed every 1-3 months. If they are outdoor cats they should be dewormed more regularly than indoor cats. It is essential to deworm all the animals in the household at the same time to prevent cross infection.


Giardia is a single-celled organism that is transmitted in water. Up to 12% of cats may have Giardia infection. This parasite typically causes diarrhoea and can sometimes cause bloody stools. In most cases, the cat will look otherwise well but in very severe cases they may vomit or stop eating.

Giardia in cats

Vets can often see the parasites when they examine a stool sample under the microscope. In some cases they may submit the stool sample for more extensive testing. Treatment can be a 5-day course of fenbendazole (a type of dewormer) or metronidazole (a type of antibiotic).

Litter tray hygiene is essential to prevent infecting other individuals of the household and to prevent reinfection. The vet may recommend that all the cats in the household are treated, because some individuals may be asymptomatic carriers.

Tritrichomonas foetus

This parasite is becoming increasingly common in cats and can sometimes occur at the same time as a Giardia infection. Laboratory tests on stools samples are require to confirm the infection. Antibiotics such as metronidazole or ronidazole are used to treat the parasite and they may need to be used long term to get the infection under control. Litter tray hygiene is essential to prevent cross-contamination between other cats in the household.

Other Infectious Causes

2. Feline panleukopenia virus/coronavirus

Feline panleukopenia virus and feline coronavirus (different to the COVID-19 virus) can cause bloody stools in cats. They are typically associated with more severe symptoms including vomiting, fever, loss of appetite, severe diarrhea, and lethargy. Cats suffering from these viruses can be very ill and often need hospitalisation and intensive treatment. In some cases, the viruses can prove fatal.

3. Bacterial infection

In some cases cats will pick up a bacterial infection that will causes bloody stools. This can either be secondary to a parasitic or viral infection or may be from eating contaminated or rotten food. In many cases, the cats will also appear unwell, vomit, or go off their food. It is essential to take your cat to the vet if they are showing other symptoms as well as bloody stool.

4. Dietary Causes

Cats’ digestive systems are very sensitive to change. If you suddenly change the diet or add an unusual ingredient, this can result in diarrhea and bloody stools. If the bloody stools occur within 24-48 hours of the diet change and the cat is otherwise well, then you can monitor the cat for a further day or two. Alternatively, changing back to the original diet may resolve the diarrhea. To prevent this from happening, slowly introduce the new food to the existing diet over a period of 1-2 weeks.

5. Inflammatory bowel disease and colitis

Inflammatory bowel disease is caused either by an allergy to an ingredient in the diet (typically a protein source) or may be because of an auto-immune condition. It can also be associated with colitis (inflammation of the large intestine) and pancreatitis (inflammation of the pancreas).

Symptoms can vary from mild, intermittent diarrhoea, with or without bloody stools, to vomiting, weight loss and a distended abdomen.

Inflammatory bowel disease is usually diagnosed after other causes of diarrhoea have been ruled out (especially parasites) and by looking for specific changes on routine blood chemistry tests. Abdominal ultrasound may be needed to assess the thickness of the small intestines and rule out other diseases.

In some cases, the vet may suggest doing intestinal biopsies to confirm the diagnosis and rule out any other diagnoses that may cause similar symptoms.

Treatment usually involves a diet change to a hypoallergenic or hydrolysed diet (e.g. Hills z/d or Royal Canin Anallergenic). And in some cases, anti-inflammatory or immunosuppressive medication (e.g. cortisone) may be prescribed to keep the symptoms under control and to prevent further deterioration.

Other potential causes

Rectal polyps: Cats rarely develop rectal polyps. These are small, benign growths just inside the anus and they can bleed from time to time. Your veterinarian will do a rectal examination on your cat and ensure that there are no polyps present. If a polyp is found they will recommend removal and will also most likely recommend that the polyp is submitted to the laboratory for analysis to ensure that it is not cancerous.

Tumors and other cancers: Cats can develop cancer in their gastrointestinal tracts that may lead to intestinal bleeding. There are a variety of cancers that may affect their digestive systems including lymphoma and adenocarcinoma. Often these cats will also be ill and have a poor appetite, weight loss, unkempt appearance, and vomiting. Your veterinarian may need to do advanced tests such as ultrasound and biopsies to diagnose the cancer. In many cases, the cancers can either be surgically removed or treated with chemotherapy. Unfortunately, some cases may be very severe and can prove fatal.

Anal gland infections: Cats have two glands that sit alongside their anus. If you imagine their anus being a clock-face, they sit at the 4 and 8 o’clock positions. These anal glands can become blocked and infected. This can then result in a bloody discharge on the stools or around the anus. In some cases, anal gland abscesses can form, and these can burst, leaving an open wound adjacent to the anus. Veterinarians will be able to assess and diagnose an anal gland infection or abscess during their examination and will prescribe a course of antibiotics in most cases. In advanced cases, sedation and flushing of the anal glands may be required. Or in cases that the infection recurs often then a bacterial culture is done to choose the correct antibiotic for that infection.

When should I be concerned about blood in my cat’s stools?

Any blood in a cat’s stools should be closely monitored. Once you notice blood in the stools take some time to note if your cat is behaving normally and eating normally. If they are looking unwell, vomiting, or not eating then they need to see a veterinarian as soon as possible. If they are otherwise normal then a wait and see approach can be taken.

If the bloody stools persist for longer than 24 hours then a veterinary visit is indicated.

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

If your cat has bloody stools but is otherwise eating well and not vomiting then you could try deworming your cat with one of the over-the-counter dewormers. A prebiotic or probiotic product can also be given. This is often in a powder form and is mixed in with their food or water. A diet change to a gastrointestinal diet such as Hills i/d or Royal Canin Gastrointestinal can also be tried.

If you see no improvement in 24 hours or if your cat is looking worse, then it is best to consult with a vet sooner rather than later.

What will happen at the vet visit?

Your vet will take a full history, including the onset of symptoms and any change in behaviour or appetite. They will also ask for further information regarding diet and previous history of illness as well as deworming history.

They will then perform a full physical examination to pick up any other symptoms that would help point them in the direction of the diagnosis. In many cases, a rectal examination may be performed to assess the stools and if there are polyps or growths in the rectum.

A stool sample analysis to rule out the various parasites will be performed. Basic blood tests including a full blood count (hematology) and clinical chemistry to assess the other organs in the body may be required if the vet needs to rule out other diseases or concurrent illnesses.

Stool sample test in a test tube
Stools sample test

Abdominal x-rays and ultrasound may be required to further assess the gastrointestinal tract and in some cases biopsy of the stomach or intestines may be required to come to a diagnosis.

sample cat xray

Cats don’t frequently give overt signs that they are ill. If they have bloody stool it is essential that a vigilant and pro-active approach is adopted to make a swift diagnosis and to begin the correct treatment as soon as possible.


Today’s Veterinary Practice magazine: GI Intervention: Approach to Diagnosis & Therapy of the Patient With Acute Diarrhea



  • Dr. Ingrid DeWet, Veterinarian

    Dr Ingrid de Wet has been a veterinarian for over 10 years. She is part owner of Country Animal Clinic in South Africa. She has a Bachelor of Veterinary Science (BVSc) from the University of Pretoria (2009).

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