Infections caused by marine vibrios appear to be an increasing problem. Gastroenteritis, soft tissue-infection and septicaemia are the most prevalent manifestations. Different environmental and traditional water quality measurements do not indicate the risk. These infections are confined to the summer and late summer with water temperatures exceeding 20 degrees C. Tourists may be exposed to an extraordinary risk, and infections may not become apparent until they have returned home. High risk groups (e.g. immunocompromized) have a high case-fatality rate. The extremely rapid onset of these infections demand aggressive antibiotic therapy and vigorous debridement at an early stage. Gastrointestinal disorders may necessitate fluid replacement and tetracycline is recommended in severe cases.