The international classification of stool form
The Bristol Scale is an international visual reference developed in 1997 at Bristol Royal Infirmary for classifying stool form into 7 types. It is used daily in clinical practice to assess bowel function, transit time and possible digestive imbalances.
Types 1-2 indicate constipation, 3-5 are considered normal, and 6-7 indicate diarrhea.
Stool fragmented into small, hard, separate lumps (similar to nuts or pebbles). Very slow intestinal transit (over 100 hours). Indicates significant dehydration and lack of fiber.
Increase soluble fiber intake (psyllium, oats), drink plenty of water (2-3 L/day), get physical activity. If it persists for more than 1-2 weeks or pain develops, see a doctor.
Sausage-shaped stool with visible lumps. Slow transit. Requires straining at defecation.
Increase dietary fiber to 25-30 g/day (vegetables, fruit, whole grains), drink enough water, keep regular meal times.
Sausage-shaped stool with surface cracks. Considered within normal range but tends toward constipation. Slightly slow transit.
Acceptable bowel function. To optimize, maintain hydration and fiber intake. Daily physical activity helps.
Perfectly formed stool: sausage- or snake-shaped, smooth and soft, passed without effort. Normal intestinal transit (24-48 hours). Indicates adequate hydration and fiber intake.
Continue your current lifestyle. Maintain hydration, fiber intake and regular physical activity.
Stool fragmented into soft blobs with well-defined edges. Easy to pass. Slightly accelerated transit. Possible lack of fiber.
Acceptable bowel function. Check whether coffee, cold drinks or spicy foods affect transit. Increasing soluble fiber may help firm up stool.
Soft stool, fragmented into pieces with ragged edges (mushy). Accelerated transit. Often associated with stress, mild infections or medication.
Plenty of fluids with electrolytes, bland diet (BRAT: bananas, rice, applesauce, toast), avoid dairy and fatty foods. If it persists more than 2-3 days, see a doctor.
Completely liquid stool with no solid component. Very rapid transit. Significant risk of dehydration and electrolyte imbalance. Often seen in intestinal infections, food poisoning, inflammatory bowel disease flares.
URGENT: oral rehydration with rehydration solutions (ORS), avoid solid food temporarily. If it persists over 24h, if there is fever, blood in stool or signs of dehydration (intense thirst, dizziness, dark urine) — seek URGENT medical care.
If types 1-2 are frequent, calculate the Cleveland Clinic Constipation Score for an objective assessment.
Constipation Calculator →Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol. 1997;32(9):920-924. PubMed