CytoFlamma® Fluor Cell-labeling solution is a lipophilic fluorescence dye for labeling hydrophobic structures in membranes and other cells. CytoFlamma® 552 Cell-labeling solution, with its low toxicity, can label cells by being applied at water-soluble culture medium, and it can also be applied for tracking of cell-cell fusion, cell adhesion and metastasis. CytoFlamma® Fluor Cell-labeling solution of BioActs that is prepared in a variety of fluorescent colors provides a great convenience for experimental design of multicolor imaging.