Understanding the Bristol Stool Scale

Published on March 5, 2026

When discussing digestive health, doctors and medical professionals frequently refer to the Bristol Stool Scale. Developed at the Bristol Royal Infirmary in 1997, this diagnostic medical tool categorizes human feces into seven distinct groups.

The Seven Categories

The scale ranges from Type 1 (separate hard lumps, difficult to pass) to Type 7 (entirely liquid with no solid pieces). Types 1 and 2 generally indicate constipation, while Types 6 and 7 indicate diarrhea. The ideal, healthiest bowel movements typically fall into Types 3 and 4, which are sausage-like, smooth, and easy to pass.

Why It Matters

Using a standardized scale removes the ambiguity from tracking your health. Instead of vague descriptions, you can use a universal metric to log your daily habits. Over time, mapping these numbers against your diet, stress levels, and water intake can highlight food intolerances or broader health trends that you might otherwise miss.