Last Updated on Feb 18, 2019

What is Foul Smelling Stool?

We are all aware that stool has an unpleasant smell even normally but improper diet and eating the wrong kinds of food coupled with indigestion can make the stool smell much worse. Bad stool odor can be a source of embarrassment in public and one should be aware of the causes of foul smelling stools so that it can be prevented.

The unpleasant odor of normal stool is due to the activity of the bacteria present in the digestive tract.

Most often excessive bad smell of the stool is due to the unhealthy foods that we consume but sometimes it may signify an underlying condition that needs to be treated.

Types of Stool

Stool is classified into seven types, based on the Bristol Stool Scale, which is used as a diagnostic clinical tool. It was developed by the Bristol Royal Infirmary, UK in 1997 and is widely used for evaluating the efficacy of treatment for various bowel diseases, including irritable bowel disease.

The classification of various types of stool is presented below:

Stool Type Consistency Clinical Indication
Type 1 Separate lumps; solid and hard Severe constipation
Type 2 Sausage-shaped; lumpy Moderate constipation
Type 3 Sausage-shaped; cracked surface Mild constipation
Type 4 Sausage-shaped; soft and smooth Normal stool
Type 5 Soft blobs; clear-cut edges Mild diarrhea
Type 6 Fluffy / mushy; ragged edges Moderate diarrhea
Type 7 Watery; no solids Severe diarrhea


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