Inspite of a high standard of hygiene, infections due to salmonellae are increasing in the highly developed countries. In the Federal Republic of Germany 36 000 cases were reported in 1976; the number of unreported cases is probably five times higher. Practical and clinical aspects make it necessary to differentiate between typhoidal, systemic infections and enteric salmonellosis, which normally remains localized in the gut. In the treatment of typhoid fever, co-trimoxazole seems to be a potent drug which can replace chloramphenicole. In cases of enteritis due to salmonellae the most important therapeutic aim is to replace the loss of fluid. This can be achieved in most cases by an oral glucose-electrolyte-solution. Antibiotics are of no value in these cases. The treatment of prolonged excretion of salmonellae with the stool remains a problem. Antibiotics usually fail. Some authors have tried drugs which tend to normalize the bacterial flora of the gut; there are no controlled studies about the effectiveness of this kind of treatment.