Seeing blood in your cat’s stool can be alarming. Sometimes a small amount of bright red blood may be linked to irritation caused by constipation or diarrhea. Other times, bloody stool can be associated with parasites, intestinal inflammation, swallowed objects, infections, toxins, or other medical problems.

The color and appearance of the blood can provide useful clues, but they cannot tell you the exact cause on their own. Bright red blood often comes from the lower digestive tract, while black, tar-like stool can indicate digested blood from higher in the digestive system.

The most useful thing you can do is look at the whole picture: How much blood is there, what does the stool look like, and how is your cat acting?

Table of Contents

Quick Answer: What Does Blood in Cat Stool Mean?

Blood in cat stool can range from mild irritation to a serious medical problem. Bright red blood may come from the large intestine, rectum, or anal area, while black, tarry stool can indicate digested blood. If your cat has a large amount of blood, weakness, pale or abnormal gums, repeated vomiting, severe diarrhea, severe pain, or marked lethargy, seek urgent veterinary care.

What does blood in cat stool look like?
Bright red blood vs. black, tarry stool
Common causes of blood in cat stool
When is bloody stool an emergency?
What should you do right now?
How veterinarians diagnose the cause
How is blood in cat stool treated?
What should you monitor at home?
Common mistakes to avoid
Frequently asked questions

What Does Blood in Cat Stool Look Like?

Blood in your cat’s poop may appear in several different ways. You might notice:

A small streak of bright red blood on the stool
Bright red blood mixed with diarrhea
Blood and mucus together
Dark red, jelly-like blood clots
Watery stool mixed with blood
Black, sticky, tar-like stool

The appearance can help your veterinarian understand where bleeding may be occurring, but it cannot replace a proper diagnosis.

Bright Red Blood in Cat Stool

Fresh, bright red blood is often called hematochezia. It usually suggests that bleeding is occurring closer to the end of the digestive tract, such as the large intestine, rectum, or anal area.

You may see bright red blood:

On the outside of the stool
Mixed with loose stool
Along with mucus
After straining to poop

A small amount can sometimes result from irritation, but recurring bleeding should not be ignored.

Black or Tarry Stool

Black, sticky, tar-like stool is known as melena. It can occur when blood is digested before it leaves the body, often because bleeding originated higher in the digestive tract.

If your cat’s stool looks truly black and tar-like, contact a veterinarian promptly.

Bright Red Blood vs. Black Stool

Stool Appearance	What It May Suggest	What to Do
Small streak of bright red blood	Lower digestive tract irritation or bleeding	Monitor closely and contact your vet for guidance
Bright red blood with mucus	Inflammation of the large intestine or another digestive problem	Veterinary advice is recommended
Bright red blood with diarrhea	Irritation or damage to the lower digestive tract	Contact your veterinarian
Large amount of fresh blood	Significant bleeding or serious illness	Seek urgent veterinary care
Black, tarry stool	Digested blood, possibly from higher in the digestive tract	Contact a veterinarian promptly

Common Causes of Blood in Cat Stool

There are many possible causes of blood in a cat’s stool. Some are relatively straightforward to treat, while others require more extensive testing.

1. Colitis or Large Intestinal Inflammation

When the large intestine becomes irritated or inflamed, cats may develop:

Frequent trips to the litter box
Straining
Small amounts of stool
Mucus
Bright red blood

The inflammation itself is a problem, but the underlying cause also needs to be identified.

2. Diarrhea

Severe or ongoing diarrhea can irritate the intestinal lining and damage small blood vessels, leading to blood in the stool.

A cat may have diarrhea because of many different issues, including diet changes, parasites, infections, stress, inflammation, or other medical conditions. The blood does not tell you which of these is responsible.

Practical example: If your cat develops diarrhea after getting into a new food, the diet change may be related. However, if blood continues to appear or your cat becomes unwell, do not assume the food is the only explanation.

3. Constipation and Hard Stool

Hard stools can scrape or irritate tissues as they pass, causing a small amount of fresh blood.

Watch for:

Hard, dry stool
Small stool pellets
Repeated straining
Frequent litter box visits with little stool produced

One important point: straining in the litter box is not always constipation. Cats with urinary problems may also strain, and this can be an emergency. If you are unsure whether your cat is passing urine, contact a veterinarian immediately.

4. Intestinal Parasites

Parasites can irritate or damage the digestive tract and may lead to bleeding.

Examples include:

Hookworms
Giardia
Coccidia

A fecal examination can help identify parasites that may be contributing to your cat’s symptoms.

Bloody stool in kittens deserves particular attention because young cats can become dehydrated or seriously ill more quickly.

5. Food Reactions or Sudden Diet Changes

Food intolerance, food allergy, or a sudden change in diet can trigger diarrhea. In some cases, severe diarrhea may contain blood.

However, avoid repeatedly switching foods in an attempt to solve the problem yourself. Multiple sudden changes can make digestive upset worse and make it harder for your veterinarian to identify the underlying cause.

6. Stress-Related Digestive Upset

Stress can trigger diarrhea in some cats, and severe diarrhea may occasionally contain blood.

Possible stressors include:

Moving to a new home
A new pet
Changes in routine
Boarding
Major household changes

Stress should not automatically be blamed for bloody stool. A cat may be stressed and also have another medical problem.

7. Foreign Bodies or Swallowed Objects

Cats sometimes swallow objects such as:

String
Thread
Bones
Pieces of toys
Hair ties
Plastic

These objects can damage or obstruct the digestive tract. Foreign bodies are a potentially serious cause of gastrointestinal bleeding.

Important: If you see string or another object hanging from your cat’s rectum, do not pull it out. Pulling may cause serious internal damage. Contact your veterinarian for guidance.

8. Inflammatory Bowel Disease and Other Chronic Intestinal Problems

Inflammatory bowel disease, or IBD, can cause significant inflammation in the digestive tract. In some cases, inflammation can become severe enough to cause bleeding.

Possible signs include:

Recurring diarrhea
Vomiting
Weight loss
Reduced appetite
Bloody stool

These signs can overlap with many other diseases, so a veterinary diagnosis is necessary.

9. Infections

Bacterial, viral, and fungal infections affecting the digestive tract can sometimes lead to intestinal bleeding.

Cats with bloody diarrhea plus vomiting, fever, lethargy, or loss of appetite should be evaluated promptly.

10. Rectal, Anal, or Local Injuries

Sometimes the blood may come from the rectum, anus, or surrounding structures rather than deeper inside the digestive tract.

Possible causes include inflammation, injuries, growths, or problems affecting nearby tissues.

11. Organ Dysfunction

Some underlying diseases can indirectly lead to gastrointestinal bleeding.

For example, certain organ problems may contribute to diarrhea, ulcers, or abnormal blood clotting. PetMD notes that kidney disease may be associated with ulcers that bleed and that liver disease can sometimes affect blood clotting.

12. Medications and Toxins

Certain medications and toxic substances can damage the digestive tract or interfere with normal blood clotting.

Never give your cat human medication unless a veterinarian specifically tells you to. Common human medicines such as acetaminophen and ibuprofen can be dangerous to cats.

If you suspect your cat has been exposed to a toxin, contact a veterinarian immediately. Do not induce vomiting unless you are specifically instructed to do so.

13. Trauma, Growths, or Cancer

Injuries to the digestive tract can cause bleeding. Benign growths and cancers affecting the digestive system may also bleed.

These causes are less likely to be identified from stool appearance alone, which is why recurring or unexplained blood should be investigated.

When Is Blood in Cat Stool an Emergency?

Seek emergency veterinary care immediately if your cat has bloody stool plus weakness, pale or abnormal gums, repeated vomiting, severe diarrhea, severe pain, collapse, marked lethargy, or a large amount of blood.

Other situations that deserve extra caution include cats that are:

Very young
Elderly
Pregnant
Living with an underlying health condition

A tiny amount of blood in an otherwise normal-acting cat may not require an immediate trip to an emergency clinic, but you should watch closely and arrange veterinary advice if the blood continues or your cat develops other symptoms.

What Should You Do If Your Cat Has Blood in Their Stool?

1. Look at Your Cat, Not Just the Litter Box

Check whether your cat is:

Eating normally
Drinking normally
Acting alert
Vomiting
Hiding
Straining
Experiencing diarrhea
Showing signs of pain

Your cat’s overall condition is one of the most important factors in deciding how urgently they need care.

2. Check the Appearance of the Stool

Take note of:

Bright red vs. black blood
The amount of blood
Hard, normal, soft, or watery stool
Mucus
Blood clots
How often your cat is pooping

A clear photo may help you accurately show your veterinarian what you saw.

3. Save a Fresh Stool Sample

If you are taking your cat to the veterinarian, bring a fresh stool sample whenever practical. A fecal examination may help identify parasites or other problems.

4. Do Not Give Human Medication

Do not give your cat aspirin, ibuprofen, acetaminophen, or other medication without veterinary advice.

Some medications that are safe for people can be toxic or dangerous for cats.

5. Contact Your Veterinarian

Contact your veterinarian promptly if:

The blood appears repeatedly
Your cat has diarrhea
Your cat is straining
Your cat is vomiting
Your cat seems uncomfortable
Your cat is eating less
Your cat is unusually quiet or lethargic

How Will a Veterinarian Diagnose the Cause?

Because blood in stool is a symptom rather than a diagnosis, your veterinarian will usually start by asking questions about your cat’s history.

You may be asked about:

Recent illnesses
Injuries or surgery
Medications and supplements
Diet and recent food changes
Outdoor access
Possible toxin exposure
Stressful events
How long the bloody stool has been happening
Whether other pets in the home are affected

A veterinarian may then recommend:

A physical examination
Fecal testing
Blood work
Urinalysis
X-rays
Ultrasound
Specialized laboratory tests
Endoscopy
Tissue biopsy in selected cases

The tests needed depend on your cat’s symptoms and what the veterinarian suspects.

How Is Blood in Cat Stool Treated?

Treatment depends entirely on the underlying cause.

For example:

Parasites may require specific antiparasitic treatment.
Constipation requires treatment appropriate to the cause and severity.
Infections may require targeted treatment.
Chronic intestinal disease may need a longer-term management plan.
Foreign bodies may require endoscopy or surgery.
Significant blood loss may require emergency stabilization.

The key point is simple: there is no single treatment for bloody stool because there is no single cause.

Avoid trying multiple home remedies, medications, or diet changes at once. Doing so may delay proper diagnosis and make it harder to determine what is helping or worsening the problem.

What Should You Monitor at Home?

If your veterinarian advises monitoring your cat, keep track of:

How much blood you see
Whether the blood is bright red or black
Stool consistency
Number of bowel movements
Straining
Vomiting
Appetite
Water intake
Energy level
Recent food changes
New medications
Possible toxin exposure

Taking a photo of the stool and recording when the problem started can also help your veterinarian.

Common Mistakes to Avoid

Waiting Too Long Because the Blood Is “Only a Little”

A tiny streak of blood may not always mean an emergency, but repeated or worsening bleeding deserves veterinary attention.

Assuming Bright Red Blood Is Always Minor

Bright red blood may come from lower digestive tract irritation, but significant intestinal disease can also cause it.

Ignoring Black, Tarry Stool

Black stool can indicate digested blood and should be investigated promptly.

Pulling on String Hanging From the Rectum

Never pull a string, thread, or other object from your cat’s rectum. It may be attached farther inside the digestive tract and pulling can cause serious injury.

Giving Human Medication

Never assume a human painkiller or stomach medicine is safe for your cat. Many common medications can be dangerous.

Blaming Everything on Stress or Food

Stress and diet changes can affect digestion, but blood in stool may also have other causes. If symptoms persist or your cat seems ill, get veterinary advice.

Frequently Asked Questions

Why Is My Cat Pooping Blood but Acting Normal?

Cats can sometimes have a small amount of blood in their stool while appearing otherwise normal. Causes range from relatively straightforward problems, such as constipation or parasites, to more serious digestive conditions.

Monitor your cat closely. If blood continues to appear or your cat develops vomiting, diarrhea, appetite changes, weakness, pain, or lethargy, contact your veterinarian promptly.

Is a Small Amount of Blood in Cat Stool Serious?

A small streak of bright red blood may sometimes result from irritation near the end of the digestive tract. However, recurring blood or blood accompanied by other symptoms should not be ignored.

Why Does My Cat Have Bright Red Blood and Mucus in Its Stool?

Bright red blood and mucus often suggest irritation or inflammation in the large intestine or lower digestive tract. There are several possible underlying causes, so recurring symptoms should be discussed with a veterinarian.

Why Is My Cat’s Poop Black?

Black, tarry stool may indicate melena, meaning blood has been digested before leaving the body. This can occur when bleeding originates higher in the digestive tract. Contact a veterinarian promptly if your cat’s stool looks truly black and tar-like.

Can Constipation Cause Blood in Cat Stool?

Yes. Hard stool and straining can irritate or damage small blood vessels near the end of the digestive tract, resulting in a small amount of fresh blood.

Can Worms Cause Blood in Cat Stool?

Yes. Some intestinal parasites can contribute to digestive tract bleeding. Hookworms, Giardia, and coccidia are among the parasites that may be associated with bloody stool.

Can Stress Cause Blood in a Cat’s Stool?

Stress can trigger diarrhea in some cats, and severe diarrhea may sometimes contain blood. However, stress should not automatically be assumed to be the cause without considering other medical possibilities.

Can a Food Change Cause Blood in My Cat’s Stool?

A sudden food change can trigger diarrhea, and severe diarrhea may sometimes contain blood. Food intolerance or allergy can also contribute to digestive symptoms. If blood continues to appear, your cat should be evaluated rather than repeatedly switching foods.

Should I Take My Cat to the Emergency Vet for Bloody Diarrhea?

Seek emergency veterinary care if bloody diarrhea is severe or occurs with weakness, pale or abnormal gums, repeated vomiting, severe pain, collapse, or marked lethargy.

How Long Should I Wait Before Calling the Vet?

Do not wait if your cat has black stool, a large amount of blood, weakness, abnormal gums, repeated vomiting, severe diarrhea, severe pain, or collapse.

If your cat has only a tiny amount of blood and otherwise seems normal, monitor closely and contact your veterinarian for guidance, particularly if the bleeding happens again.

Final Thoughts

Blood in cat stool can have many causes, ranging from temporary digestive irritation to serious disease. The appearance of the blood can provide clues, but it cannot diagnose the problem.

Bright red blood often suggests bleeding closer to the end of the digestive tract, while black, tarry stool may indicate digested blood. The amount of blood and your cat’s overall condition are equally important.

If your cat has repeated bleeding or develops vomiting, severe diarrhea, weakness, pain, abnormal gums, lethargy, or other concerning symptoms, seek veterinary care promptly. The safest approach is to document what you see, avoid giving human medication, and get professional guidance when blood appears in your cat’s stool.