The diameter of normal stool is about 2cm~4cm, there is no clear clinical specification, and there are large individual differences. As long as there is no obvious abnormality in the stool, it is mostly normal; if there is pus and blood, blood in the stool, change in the shape, and obvious abnormality in the stool with the usual changes, then it is mostly abnormal, and need to pay attention to it in time. Due to the different dietary habits of each person, different bowel habits, and even the different function of the anal sphincter, will have an impact on the thickness of the stool. Therefore, there is no uniform standard for bleeding from the stool. As long as the stool maintains a more uniform diameter for a long period of time and does not change significantly within a short period of time, even if it is a little too thick or too thin, it is mostly normal. If in a short period of time appeared in the stool becomes thin, the stool is not shaped, may be due to intestinal polyps, intestinal occupational lesions and other diseases caused, it is recommended to consult a doctor in time, to clarify the cause of the disease.