Although the micronucleus assay with Vicia faba root tip cells is a canonical way to detect the genotox ̄icity of environmental pollutants, there are still some important issues that are worth in ̄depth discussion and inves ̄tigation in its methodology. After illustrating how to correctly observe the micronucleus and chromosome aberra ̄tions, including chromosome fragment, chromosome loss and chromosome bridge, in the Viciafabaroot tip cells we suggested that the dividing ̄phase cells and their chromosome aberrations should been taken account o...