PROBLEM TO BE SOLVED: To provide a tooth surface dyeing coating liquid capable of uniformly dyeing the whole tooth surface including dental plaque, having favorable drying characteristics for evenly applying the tooth surface, and capable of forming a dyed coating film having necessary strength for evaluating a removal degree of tooth surface contamination, and evaluation method of removal of tooth surface contamination for easily and reproducibly evaluating a removal degree of the tooth surface contamination by chewing of a chewing gum.SOLUTION: The tooth surface dyeing coating liquid includes 28.0-33.0 wt.% of shellac, and 4.0-17.0 wt.% of food color in the whole weight of the tooth surface dyeing coating liquid. The tooth surface contamination removal evaluation method is executed using the tooth surface dyeing coating liquid and includes the following steps of: (1) cleaning a tooth surface； (2) applying the tooth surface dyeing coating liquid to the tooth surface to dye the whole tooth surface； (3) drying the dyed tooth surface and forming the dyed coating film； (4) chewing a chewing gum； and (5) evaluating a removal degree of the tooth surface contamination from a difference between dyed coating film forming areas before and after chewing the chewing gum.
