The Bristol Stool Form Scale (BSFS), or Bristol stool scale, is a chart that can help classify stools into seven groups. Characterizing the stool based on its consistency can help identify if it is a healthy bowel movement.

The bowel is the part of the digestive system that allows people to absorb nutrients from food and expel the waste that the body cannot use. If feces pass too quickly or too slowly, it may indicate a problem with the bowels.

This article explains the BSFS and suggests tips to improve bowel health and function.

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In 1997, Dr. Kenneth Heaton developed the BSFS, a diagnostic tool to help classify stools into seven categories. Healthcare professionals can use the chart as a practical guide in assessing how long a stool has spent in the bowels.

The scale uses stool consistency to describe and categorize feces. Dr. Heaton devised the BSFS as a quick, inexpensive, and reliable way to classify stools visually without the need for laboratory testing.

Healthcare professionals can use the BSFS to help assess the condition of the bowel and measure the effectiveness of certain treatments. For example, they may use the BSFS to help diagnose irritable bowel syndrome (IBS).

The BSFS is a scale that classifies stools, ranging from the hardest to the softest. Experts consider types 1 and 2 to be uncharacteristically hard and indicative of constipation, while types 6 and 7 are unusually loose and may indicate diarrhea. Healthcare professionals generally consider types 3, 4, and 5 to be the most typical.

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By Diego Sabogal

The BSFS categorizes stool into seven types.

Types 1 and 2

Type 1 has the appearance of separate hard lumps, while type 2 is sausage-shaped but lumpy. Both types could indicate constipation, as these stools are hard, dry, and difficult to pass. They may also be darker in color. This occurs when food passes too slowly through the digestive system and the colon absorbs too much water.

To help treat constipation, people can consume more fiber, drink more water, perform regular physical activity, and try bowel training.

Individuals may also consider trying over-the-counter (OTC) laxatives for a short time. In more severe cases, a healthcare professional may prescribe medications to soften the stool and encourage the colon to pass feces.

Learn more about laxatives for constipation.

Types 3, 4, and 5

Type 3 has a shape similar to a sausage but with cracks on the surface, while type 4 has a comparable appearance to type 3 but with a smooth and soft surface. Experts generally consider these types to be the most healthy and typical stool forms.

Type 5 stools are soft blobs with clear-cut edges that a person can pass easily. Some may also consider this type to be typical in those without bowel issues, while others may suggest it is too loose and may imply diarrhea.

Types 6 and 7

Type 6 is a mushy stool that appears to consist of fluffy pieces with ragged edges, while type 7 is entirely liquid with no solid pieces. These types of stools may suggest a person is experiencing diarrhea, as the stools are loose. They may also be lighter in color. This is due to passing the stool through the digestive system too quickly and the bowel is unable to absorb water.

To help treat diarrhea, individuals need to drink plenty of fluids to maintain hydration and consider taking OTC antidiarrheal medication. For chronic or persistent cases of diarrhea, people can speak with a healthcare professional, who can identify the cause and prescribe appropriate medications.

Learn more about treating diarrhea at home.

The bowel consists of the small and large intestines, which both play an important role in keeping people healthy. They allow the body to absorb fluid and nutrients from food and process and expel the waste.

Signs of a healthy bowel can include:

  • regular bowel movements of well-formed (types 3 and 4) stools
  • being able to hold on for a short amount of time after first feeling the urge to pass a stool
  • defecating within roughly a minute of sitting on the toilet
  • passing a stool without any pain or need to strain
  • completely emptying the bowel when having a movement

In addition to having a healthy diet, drinking plenty of fluids, and getting regular exercise, people can try other strategies to improve their bowel health and function.

These may include:

  • Bowel training: Individuals can attempt to train themselves to have a bowel movement at consistent times each day. For example, people can try to pass a stool shortly after eating breakfast. It is also advisable for a person to allow plenty of time and use the bathroom as soon as they feel the need to go.
  • Positioning: Maintaining appropriate toilet posture may make it easier for individuals to have a bowel movement and avoid straining. This typically involves relaxing, placing the feet on a footstool to ensure the knees are higher than the hips, leaning forward, bulging out the abdomen, and straightening the spine.
  • Changing medications: If a person suspects that a medication or supplement may be affecting their bowel movements, they should discuss this with their healthcare professional. They may be able to change the dose or suggest a different medication.
  • Dietary changes: As well as eating more fiber, it may be beneficial for people to consider avoiding foods and drinks that may irritate their stomachs. This may include alcohol, caffeine, and fatty foods. However, before making any drastic dietary changes, it is advisable to speak with a medical professional.

If a person is persistently passing stools at either end of the BSFS or switching from one end of the scale to the other, it is advisable that they consult with a healthcare professional.

A healthcare professional can help identify the potential cause of abnormal bowel movements and recommend suitable treatments to allow an individual to pass regular and healthy stools.

The BSFS is a diagnostic tool that people can use to classify their stools based on their appearance. The chart ranges from type 1 (hard) to type 7 (loose) and may identify problems with bowel movements through the shape and consistency of the stool.