Numerous complications of enteric infections have been described, including persistent diarrhea, reactive arthritis, and Guillain-Barre syndrome. We determined the frequency of self-reported complications of enteric infections in a pilot study in the California site of the Foodborne Diseases Active Surveillance Network. From 1 April 1998 through 31 March 1999, active surveillance identified 1454 infections in Alameda and San Francisco counties, of which 52% were Campylobacter infections, 22% were Salmonella infections, 15% were Shigella infections, 6% were Cryptosporidium infections, 2% were Escherichia coli O157:H7 infections, 2% were Yersinia infections, and 1% were Vibrio infections. We mailed surveys to 1331 eligible participants, and 571 (43%) were returned. A new health problem following infection was reported by 153 (27%) of the respondents: 12 (8%) reported new onset of joint pain and 53 (35%) reported new gastrointestinal symptoms, of whom 38 reported persistent diarrhea, including 2 who reported irritable bowel syndrome. Three respondents reported hair loss. The frequency, nature, and etiology of these complications merit further investigation.