There are only very few reports in our literature on problems and pitfalls of the differential diagnosis and present incidence of acute abdominal salmonellosis and shigellosis. Based on evaluated results of a three-year investigation from their department the authors draw attention to the relatively frequent concurrent incidence of acute abdomen and infectious diarrhoeal disease, the difficulty of differential diagnosis and indication of surgery even when the results of cultivation examinations are known due to the common interlinked symptomatology and coincidence. The symptoms imitating acute abdomen in infectious diarrhoeal diseases predispose by concentration of infectious patients in surgical departments the development of nosocomial infections and epidemics.