(1) Cleft tongue is characterized by various cracks and fissures on the tongue surface, with different depths, deficiency of the main yin and blood, and dampness invasion due to spleen deficiency. The tongue is crimson and cracked, which is mostly caused by excessive heat and yin injury. The tongue is pale and cracked, which is mostly caused by blood deficiency and dryness. The tongue is pale, white, fat and tender, with teeth marks and cracks at the edge, mostly due to spleen deficiency and wet invasion. If the tongue is born with cracks and fissures, covered with tongue coating and without discomfort, it is congenital cleft lip and palate. (2) Toothed tongue is characterized by tooth compression at the edge of tongue body, which is mainly responsible for spleen deficiency and dampness. The tongue is light, fat and moist, and there are teeth marks on the edge of the tongue, which are mostly caused by cold and dampness or stagnation of yang deficiency and water and dampness. Those with red tongue and teeth marks on the edge of the tongue are mostly spleen deficiency or qi deficiency. Red tongue, swollen mouth, tooth marks, manifested as damp-heat stasis and excessive phlegm. (3) The tongue is big and thick, full of mouth, which is called fat tongue.