Treatment of patients is symptomatic if the causative agent is unknown, with the exception of symptoms suggestive of botulism. Consider the need of therapy again when the cause of food poisoning is known. The aim is to stop an epidemic and to disclose the cause. Stool specimens should be taken from the index case(s), and from persons with and without symptoms around and in connection with the index case. In the case of a large epidemic the faecal specimens should be examined for Salmonella, Shigella, Campylobacter and Yersinia as well as viral agents. A suspected water-borne epidemic or an epidemic involving a large group of people indicates screening of faecal specimens. The target groups and the number of sampled persons should be decided with the laboratory or environmental authorities. A specimen of the suspected food item should be taken.