Epidemic surveillance is an effective means to determine the characteristics of acute diarrhea and the benefits of disease control and prevention. The epidemiological, clinical and etiological data of adult acute diarrhea in Shanghai were collected and analyzed. Of the 2,430 acute diarrhea patients, the 162 subjects that were sampled (sample ratio: 16:1) had an average age of 44 18; 142 (87.7%) patients had a history that indicated the ingestion of contaminated food and 40 (24.7%), 54 (33.3%), and 73 (45.1%) patients had diarrhea attributed to viral, bacterial and unknown etiological origins, respectively. Viral diarrhoea is mainly prevalent in the winter and spring months, while bacterial and diarrhoea of unknown aetiology occur mainly in the summer months. The average age of the unknown aetiology group (48 19) was significantly older than that of the viral diarrhoea group (39 16). The number of patients with vomiting in the viral group (30.6%) was significantly higher than that in the bacterial (17.1%) and unknown aetiology (8.2%) groups. Viral and bacterial infections are the main cause of acute diarrhoea in Shanghai. However, further effective technological means are needed to improve the surveillance, control and prevention of acute diarrhoea.