Acute diarrhea is generally defined as diarrhea that has been present for less than several weeks. It presents with a sudden change in bowel habits, resulting in loose and frequent stools more voluminous in nature, sometimes associated with fever, malaise and/or dehydration. Causes - Infections are the most common cause of acute diarrhea. The organisms we see most frequently are E. Coli, Salmonella, Shigella, Clostridium Difficile (C. Difficile), Campylobacter and Giardia, as well as a variety of viral causes. Food poisoning is another cause of acute diarrhea, which is a result of various bacteria infecting food that has generally been stored improperly. Numerous medications may cause diarrhea. These can include antacids, antibiotics, antihypertensive medications, laxatives, magnesium supplements, potassium supplements and various cardiac medications. Ingestion of poorly-absorbed sugar may lead to diarrhea in certain people. These include fructose, lactose, mannitol and sorbitol. Some of these products are present in sugarless foods or drinks, and this is a quite common cause of acute diarrhea. Diagnosis - An evaluation of acute diarrhea consists of a visit with the doctor that includes a history and physical examination. Sometimes a flexible sigmoidoscopy is performed to look at the lining of the colon, and we may perform stool cultures and analysis to look for infectious causes. Blood tests or abdominal x-rays may also be considered. Treatment - Treatment for acute diarrhea consists mainly of replenishing fluid and electrolytes, along with antibiotics and antidiarrheal agents. Most patients respond well to outpatient treatment, but on occasion if severe dehydration develops or signs of toxicity occur, like fever or severe pain, then in that situation the patient may need to be hospitalized.