At the journal club meeting held on October 29, 2018, basic principle of flow cytometry and its application in medical researches was discussed. Flow cytometry as an instrument capable of simultaneous measuring characteristics of cells such as size and granularity was introduced. Additionally, the basic understanding of flow cytometry technology essential for all users in combination with the methods used to analyse and interpret the data were discussed. Moreover, the potential of Fluorescence-Activated Cell Sorter (FACS) method in comparison with flow cytometry for toxicology applications was introduced.