Acute diarrhea is defined as an abnormally frequent discharge of semisolid or fluid fecal matter from the bowel, lasting less than 14 days. More than three millions cases of acute diarrhea, presumably due to intestinal infections, are seen in general practice every year in France. Most of the cases are benign and resolve under symptomatic treatment within 3 days, without need for biological tests or antibiotics. In special contexts (septicemic syndrome, visible blood in stools, severe dehydration, patients at risk of severe sepsis [valvulopathy]), biologic tests and probabilist antibiotic treatment are required. Hygiene, rehydration and diet recommendations are always part of the treatment of acute diarrhea, in addition to the symptomatic treatment of diarrhea and other digestive symptoms. Antibiotic-associated diarrhea is clinically benign in most cases, and attributed to transient dysbiosis of gut microbiota. In the remaining cases, diarrhea is the clinical expression of intestinal infection by Clostridium difficile, that should be treated with metronidazole, or the clinical expression of a Klebsiella oxytoca-associated colitis that usually spontaneously resolves after stopping antibiotics.