An accumulation of hardened or inspissated feces (thickened, dried, or made less fluid by evaporation or absorption of liquid components) in the rectum or sigmoid colon that the individual is unable to move out by defecation.

Diarrhea may be a sign of fecal impaction, since only liquid material is able to pass the obstruction.

Sometimes fecal impaction may cause urinary incontinence because of pressure on the bladder.

People who are dehydrated; nutritionally depleted; on long periods of bed rest; receiving constipating medications; such as, iron or opiates; or undergoing barium radiographic studies are at risk of developing fecal impaction.

Prevention includes adequate ingestion of bulk food, fluids, exercise, regular bowel habits, privacy for defecation, and occasionally stool softeners or laxatives.