The Bristol stool scale is used to assess the physical appearance and form of fecal samples. There are seven types included in the scale, ranging from solid feces to watery diarrhea. The scale was developed by Dr. Ken Heaton of the University of Bristol in England as a means of estimating fecal transit time, but is generally used to help evaluate treatments for various bowel diseases. In the United Kingdom, the Bristol stool scale is sometimes called the Meyers scale.
Each category in the Bristol stool scale describes a specific form. Type 1 stools are separate small hard lumps, while type 2 stools are sausage-shaped, but lumpy. These two stool types are indicative of constipation. Type 3 stools, which are sausage-shaped with a cracked surface, are considered normal when they are excreted without straining, but can sometimes indicate mild constipation.
Type 4 stools are considered the most indicative of normal bowel movements and good digestive health. These stools are easy to pass, are smooth and soft, and are shaped like a sausage or snake. Type 5 stools are soft separate lumps which are easy to pass. While these stools are usually considered normal, they can sometimes indicate diarrhea.
In most cases, type 6 and 7 stools are associated with diarrhea. Type 6 stools are mushy lumps with ragged, undefined edges, while type 7 stools are very watery and might even be entirely liquid. Both of these types of bowel movements are usually passed with a high degree of urgency.
Although the intended purpose of the Bristol stool scale was to estimate the time taken for food to travel through the digestive tract and emerge as fecal waste, the validity of this idea was soon called into question. The main reason for this is the fact that fecal transit time is not the only factor that determines the form a bowel movement takes; however, the scale remains useful to doctors and researchers for two reasons.
First, the seven categories of the scale provide a preliminary method for determining the effects of a particular treatment. By monitoring a patient’s bowel movements and comparing their appearance to the the scale, a doctor or nurse has an immediate measure of whether a given treatment has had any effect. The second reason is that patients who are shy or otherwise reluctant to discuss their bowel movements can simply point to a comparison picture of the type their movement most closely resembles.
The Bristol stool scale is most often used by medical professionals as a means of assessing stool samples, but anyone interested in monitoring their bowel habits can use the scale at home. Of course, this is no substitute for medical advice from a doctor or other healthcare worker. Any significant or persistent changes in digestive health or bowel motions can indicate the advent of disease, and should be discussed with a doctor.