The revised guideline on 'Acute diarrhoea' from the Dutch College of General Practitioners covers the diagnosis and management of suspected acute infectious diarrhoea. Acute diarrhoea resulting from infectious gastroenteritis is often caused by a virus and is usually self-limiting; stool testing is rarely indicated. The main complication of acute diarrhoea is dehydration, although this is rare in the Netherlands. Children under 2 years old and patients over 70 are at an increased risk of dehydration. Dehydration is a clinical diagnosis based on a combination of patient history and physical examination. DNA diagnostic methods such as polymerase chain reaction (PCR) are now available for stool testing, in addition to stool culture and the triple faeces test (TFT). PCR is preferred for its better test properties. Treatment with oral rehydration salts (ORS) is indicated for patients with dehydration and may also be useful in patients at an increased risk of this event. Acute diarrhoea after hospitalisation or after visiting the tropics or subtropics merits special attention on account of the risk of infection with unusual pathogens and the consequences with regard to management.