Stool formation and thinning may be caused by improper dietary structure, hemorrhoids, rectal space-occupying lesions and other reasons. 1. Improper dietary structure: consuming too much fatty food or consuming more food containing a small amount of dietary fiber can lead to softer stools, which can be easily squeezed and become thin. 2. Hemorrhoids: External anal hemorrhoids can cause the stool to change shape and become thinner when it is discharged. 3. Rectal space-occupying lesions: such as rectal polyps, rectal cancer, etc., which can lead to the stool passing through the rectum by extrusion, the phenomenon of thinning stool formation. It is recommended that patients with thinning stools should go to the hospital in time to clarify the cause, and if treatment is needed, standardized treatment should be carried out under the guidance of the doctor.