Read on to learn more about the Bristol Stool Chart and the seven stool classifications.

The Bristol Stool Chart is a guide to different stool types. S. J. Lewis and K. W. Heaton developed the Bristol Stool Chart in 1997 in Bristol, the United Kingdom.
There are seven different classifications of stool on the Bristol Stool Chart. The chart can help clinicians to determine how long feces spent in the bowel, which can in turn help them diagnose conditions of the bowel.
Why is the Bristol Stool Chart important?
Doctors can reach a quicker and more accurate diagnosis by comparing different types of stool.
Medical professionals can quickly classify stool into one of seven types with the Bristol Stool Chart. This can help them determine how long stool has spent in the bowel and whether or not the chart considers the stool to be healthy.
There are seven different types of stool on the Bristol Stool Chart. They are classified as follows:
- Type 1 and type 2: Stool is firm and lumpy. This may indicate constipation.
- Type 3 and type 4: Stool is sausage-shaped and easy to pass. This is the healthiest stool to aim for.
- Type 5, type 6, and type 7: Stool is soft, mushy, or watery. This may suggest diarrhea.
Type 1
Stool appears as separate hard lumps. They may resemble nuts and can be hard to pass.
Type 2
Stool is sausage-shaped. It also appears lumpy.
Type 3
Stool is sausage-shaped. Cracks appear on the surface.
Type 4
Stool is like a sausage or a snake. It is smooth and soft.
Type 5
Stool presents as soft blobs with clear-cut edges. It is easy to pass.
Type 6
Stool is mushy. It is made up of individual fluffy pieces with ragged edges.
Type 7
Stool is watery with no pieces. It is entirely liquid.
Medical professionals consider Bristol stool types 3 and 4 to be the best types of stool. Stool should be sausage-shaped and easy to pass. It can be smooth, or there may be cracks on the surface.
A healthy stool is typically brown in color. Stool is brown due to the presence of bile and bilirubin. Bilirubin occurs when red blood cells naturally break down in the intestine.
According to the Bristol Stool Chart, the ideal stool will be sausage-shaped and easy to pass.
Certain shapes and types of stools may be unhealthy, as they can indicate problems with bowel movements or other health concerns.
Constipation
On the Bristol Stool Chart, stool types 1 and 2 indicate constipation. Constipation is a common condition, affecting around 16 in every 100 adults in the United States. This number increases to around 33 in every 100 adults over the age of 60.
Constipation can occur due to:
- eating a diet low in fiber
- not drinking enough water or fluids
- spending long periods sitting or lying down
- not getting enough exercise
- experiencing side effects of medication
You may have constipation if you have fewer than three bowel movements in a week. In some cases, this can be a sign of an underlying medical condition or a blockage in the digestive tract.
Constipation may be a symptom of the following:
- IBS
- celiac disease
- Parkinson’s disease
- diabetes
- hypothyroidism
- diverticular disease
- proctitis
Contact your doctor if your constipation persists, or if you experience constipation alongside any of the following symptoms:
- abdominal pain
- inability to pass gas
- vomiting
- lower back pain
- unintentional weight loss
- fever
- rectal bleeding
- bloody stool
Learn more about constipation.
Diarrhea
On the Bristol Stool Chart, stool types 5, 6, and 7 indicate diarrhea. This can occur as:
- acute diarrhea, which lasts for 1–2 days before usually going away on its own
- persistent diarrhea, which lasts for 2–4 weeks
- chronic diarrhea, which lasts at least 4 weeks and may come and go
Acute diarrhea is the most common type of diarrhea, with around 179 million cases occurring in the U.S. each year.
Symptoms that can occur alongside diarrhea include:
- abdominal pain
- nausea
- cramping
- loss of control of bowel movements
If diarrhea occurs as a result of an infection, you may experience symptoms such as:
Severe diarrhea can result in dehydration and malabsorption. Contact your doctor if you have severe or chronic diarrhea.
Stool color
The color of your stool can indicate an underlying health concern. A healthy stool is typically brown in color, but your stool may also be black, red, blue, orange, yellow, or green.
- Black stool: Black stool usually indicates that there is a bleed in your upper gastrointestinal (GI) tract. This can be serious and should not be ignored. Stool may also appear black if you eat dark foods or take iron supplements.
- Red stool: If your stool is bright red or bloody, this can indicate a bleed in your lower GI tract. Bleeding may also be a result of anal fissures, a fistula, hemorrhoids, or consuming red foods.
- Blue stool: Stool that is blue is usually a result of eating blue foods, such as blueberries, or consuming foods with blue dye.
- Orange stool: Consuming excess beta-carotene can make your stool orange. This includes beta-carotene from supplements, carrots, squash, sweet potato, and some leafy green vegetables.
- Yellow stool: Bile can cause stool to appear yellow or pale. Pale stool may also indicate problems with your liver or gallbladder.
- Green stool: Green stool can be a result of eating a lot of leafy vegetables or food with green coloring. Green poop may also occur if the stool passes too quickly through the large intestine.
Contact your doctor if you notice changes in the color of your stool.
If you experience changes in your bowel habits, or if you frequently experience diarrhea or constipation, contact your doctor for advice. They will be able to carry out tests to determine the underlying cause.
The tests may depend on any other symptoms you present but can include:
- Blood tests: A blood test can help rule out certain conditions.
- Stool tests: Your doctor may request a stool sample to send to the laboratory for analysis. The lab can help detect infections or the presence of blood.
- Endoscopy procedures: During an endoscopy, your doctor will take a closer look inside your GI tract. These procedures include upper endoscopy, colonoscopy, sigmoidoscopy, and capsule endoscopy.
- Imaging tests: Your doctor may carry out an imaging test alongside an endoscopy procedure to achieve a more thorough overview of your digestive health. Imaging tests include X-rays, CT scans, and MRI scans.
While it may not always be possible to avoid complications or conditions affecting the bowels, you can take steps to have a healthier bowel.
Tips for a healthier bowel include:
- drinking 2–5 liters of water per day
- eating a diet rich in fiber, which can include:
- whole wheat or seeded whole grain bread
- whole grains such as whole wheat pasta
- potatoes with the skin on
- oatcakes
- unsalted nuts
- seeds
- leafy green vegetables such as kale or spinach
- pulses such as beans, lentils, or chickpeas
- consuming all food groups in meals, particularly protein, carbohydrates, and fats
- having a bowel movement when you need to
- keeping active
View our Digestive Health hub for more information.
The Bristol Stool Chart classifies stool into seven different types. Types 1 and 2 refer to stools that occur with constipation, while types 5, 6, and 7 suggest diarrhea. The ideal stools are types 3 and 4.
Clinicians can use the Bristol Stool Chart to get a quick overview of the health of your stool. This in turn can help them to diagnose conditions that affect the stool.
Contact your doctor if your stool persistently resembles types 1, 2, 5, 6, or 7. Also contact your doctor if you notice changes in your bowel habits or the color of your stool.