Objective: To study the relationship of purple tongue and its regional blood flow.
Methods: Laser-Doppler flow meter was employed to test the volume and velocity of blood flow at different sites of purple tongue (56 cases) and normal tongue (54 cases), and the test results were analyzed.
Results: The volume of blood flow of purple tongue was significantly lower than that of the normal tongue (P<0.01), while the velocity was significantly higher (P<0.01). The volume and velocity of blood flow at different sites of the tongue were similar without significant difference.
Conclusion: The volume of blood flow of purple tongue is decreased and the velocity increased. Purple tongue may be caused by dysfunction of the microcirculation of the tongue.