Modern epidemiology relies heavily on quantifying biological phenomena and their relationships with the environment and other factors. Guttation is a physiological phenomenon resulting in oozing of drops of xylem sap on the tips or margins of leaves (hydathodes) of some vascular plants. Many studies revealed that this pathogen suspended in the water droplets gain entrance through the hydathodes into the vascular tissues. The water droplets secreted from hydathodes contain trace amounts of organic and inorganic substances that may serve as chemical attractants as well as nutrient sources for plant pathogenic bacteria. So this study overviewed the importance of this phenomenon in epidemiology of Bacterial blight of rice.