Rice-water stools are characteristic of infection with Vibrio cholerae due to its production of cholera toxin. This toxin causes massive secretion of electrolytes and water into the intestinal lumen, leading to profuse, watery diarrhea that resembles rice water. The stool is typically pale, watery, and flecked with mucus, but without blood or pus. This massive fluid loss can rapidly cause severe dehydration and hypovolemic shock if untreated. The pathophysiology and clinical presentation of rice-water stools are distinctive features used to diagnose cholera.

Reference: Harrison's Principles of Internal Medicine, Kasper et al., 20th Edition.