Osmotic diarrhea results from the presence of osmotically active, poorly absorbed solutes in the bowel lumen that inhibit normal water and electrolyte absorption.
Comment:
Osmotic diarrhea involves an unabsorbed substance that draws water from the plasma into the intestinal lumen along osmotic gradients. Secretory diarrhea results from disordered electrolyte transport and, despite the term, is more commonly caused by decreased absorption rather than net secretion. Inflammatory diseases cause diarrhea with exudative, secretory, or osmotic components.