Objective:Studies quantifying relationships between floods and diarrheal diseases have mainly been conducted in low-latitude regions.Its therefore increasingly important to examine these relationships in midlatitude regions,where they may have significant public health implications.This study aimed to examine the association between floods and bacillary dysentery in the city of Dalian,China.Methods:A generalized additive mixed model was applied to examine the association between floods and bacillary dysentery.The relative risk(RR)of flood impact on bacillary dysentery was estimated.Results:A total of 18,976 cases of bacillary dysentery were reported in Dalian during the study period.Two weekslagged effect was detected from the impact of floods on bacillary dysentery.The RR of flood impact on bacillary dysentery was 1.17(95%Cl:1.03-1.33).Conclusions:Floods have significantly increased the risk of bacillary dysentery in Dalian.More studies should focus on the association between floods and infectious diseases in different regions.Our findings have significant implications for managing the negative health impact of floods in the midlatitude region of China.(Disaster Med Public Health Preparedness.2016;page 1 of 6).