OBJECTIVE: To study the changes and clinical significance of circulating endothelial cells in childhood acute bacillary dysentery. METHODS: Thirty children with acute bacillary dysentery (treatment group), and 30 cases of viral enteritis (control group) were studied. The treatment group was further divided into two sub groups: treatment sub groupⅠ (8 cases with toxic bacillary dysentery) and treatment sub groupⅡ (22 cases with ordinary bacillary dysentery). The number of circulating endothelial cells (CEC) in the blood was determined by the flow cytometry on the 1st day and the 5th day of the disease. RESULTS: The CEC level of the treatment group on the 1st day ( 4.57 ± 0.69 ) was higher than that in the same group on the 5th day ( 1.06 ± 0.15 ), and higher than the control group on the 1st day ( 1.22 ± 0.23 ) and 5th day ( 1.18 ± 0.20 ) (P< 0.01 ). The CEC level of the treatment sub group Ⅰwas markedly higher than that in the treatment sub group Ⅱ on the 1st day [( 5.43 ± 0.50 ) vs ( 4.25 ± 0.44 )] (P< 0.05 ). There was no difference in the CEC level between the two treatment groups on the 5th day. CONCLUSIONS: CEC may be important in discerning children with acute bacillary dysentery, and be a pathologic target in making an early diagnosis and selecting effective treatments.