Abstract: The present disclosure relates to a plaque disclosing composition containing riboflavin 5-phosphate sodium, a method for disclosing a plaque, wherein the plaque is an acquired pellicle, and a method for collecting and analyzing an information about the amount and characteristics of dental plaque by analyzing the color and intensity of fluorescence emitted by riboflavin 5-phosphate sodium for effective treatment of dental plaque even at the early stage.