Anyone can occasionally have narrow stools. As long as bowel movements are otherwise normal, this usually isn't cause for concern. However, several possible causes of thin stools warrant attention.

Diverticulitis can cause irregular stools, alternating between diarrhea and constipation, along with unusually strong-smelling and/or bright red, maroon, or tarry stools. Diverticulitis is caused when ...

Hard stools are a common occurrence. They occur when stools pass through the colon too slowly, allowing the colon time to absorb too much water from the stool. The stools then become hard and dry.