How does the large intestine absorb water from digestive contents?

The primary function of the large intestine is the absorption of water and electrolytes from digestive residues, a process that transforms liquid chyme into solid fecal matter.123

This absorption is facilitated by the physical movement of the intestinal contents. Churning movements within the colon gradually expose the digestive residue to the absorbing walls of the intestine, allowing for the efficient uptake of water and solutes. As water is removed, the chyme progressively thickens.21

While the small intestine primarily absorbs water secondary to the absorption of electrolytes, the large intestine serves as a reservoir that further concentrates these contents. By absorbing approximately 1.5 to 2 liters of fluid daily and reducing it to about 150 ml, the colon plays a critical role in maintaining the body's fluid balance and the osmolality of the blood. Additionally, the large intestine secretes mucus to lubricate the remaining material, facilitating its transport toward the rectum for storage and eventual excretion.43