Hard stool

Firm fecal matter that is dry, overconcentrated, and difficult or painful to evacuate, typically reflecting prolonged colonic transit. Possible causes are dehydration, low fiber diet (lack of fruits, vegetables, and whole grains), inactivity, suppressing bowel movements, medications (opioids, antidepressants, iron supplements, antacids, calcium channel blockers), irritable bowel syndrome, intestinal tumor, hypothyroidism, diabetes, Parkinson's disease, multiple sclerosis, spinal cord injury, or pregnancy.