Although the existence of chronic carriers of Vibrio cholerae has been posited, the information in this regard is limited and contradictory. In order to determine the usefulness of the encapsulated string test (enterotest) for detecting V. cholerae in duodenal secretions of biliary origin (biliduodenal secretions), 59 patients (30 males and 29 females) over the age of 15 with clinically and bacteriologically diagnosed cholera were evaluated. All the patients, who were treated at the María Auxiliadora Departmental Hospital in Lima, Peru, were put on the same rehydration regimen and were given 2 g of tetracycline daily for 3 days. Between 24 h and 7 days after completion of the antibiotic treatment the first control tests were performed: culture of biliduodenal secretions obtained using enterotest and culture of feces obtained by rectal swab. No patient had diarrhea at the time of the first test. The biliduodenal secretion cultures revealed the presence of V. cholerae in five patients (8.5%) (four females and one male), while the fecal culture yielded negative results in all cases. One week later the control test was repeated on four of the five patients. All the biliduodenal secretion cultures were negative and only one fecal culture was positive at this stage. The patient in question was subjected to the same control tests one week later and both were negative. It is concluded that enterotest can be a simple, well-tolerated, low-cost method for detecting V. cholerae carriers.