The Bristol stool scale is a chart that categorizes stools into seven types based on appearance, explains Gut Sense. It features both images and written descriptions of each stool type. Patients with bowel-related concerns use the scale as a visual aid when describing their symptoms to doctors.
The first type of stool on the Bristol Stool Scale has the appearance of hard, nut-sized lumps that are difficult to pass, according to Gut Sense. This stool type may occur due to a lack of healthy bacteria and is common in people who have recently taken antibiotics. The second type is lumpy, sausage-shaped stool. This type of stool places patients at risk for complications such as diverticulosis and anal canal laceration because it is larger in diameter than the maximum size of the anal canal opening. Stool type three is also sausage-shaped, but it has cracks in it, and like type two, type three requires straining to pass, which potentially results in damage to the anal canal.
Stool type four, which is common for people who have one bowel movement per day, is smooth, soft and snake-like in appearance, as described by Gut Sense. The fifth type, which people who defecate two or three times a day tend to have, consists of soft, easily passable blobs. Type six consists of mushy pieces of stool that may be hard to hold in, while watery diarrhea is the seventh type on the chart.