Sunken tongue is not a sign of Qi deficiency. Qi deficiency of the tongue for the tongue color pale white tongue body thin thin, mostly with blood deficiency; tongue in the depression is generally considered to be related to the weakness of the spleen and stomach. Qi deficiency causes blood deficiency, blood does not glorify the tongue, the tongue of qi deficiency is seen in the tongue pale white, with blood deficiency, manifested as a thin tongue. Depression in the tongue is not a sign of simple qi deficiency, but generally indicates weakness of the spleen and stomach. When the Spleen and Stomach are weak in Qi, the Spleen is not healthy, and the essence of water and grains cannot generate Qi and blood, resulting in the lack of Qi and blood moistening in the tongue, and the depression appears. Yang deficiency of the Spleen and Stomach (Yang deficiency of the Spleen and Stomach) results in a lack of blood transportation and the inability to glorify the tongue, resulting in a sunken appearance. Yin deficiency of the Spleen and Stomach (insufficient Yin fluid in the Spleen and Stomach), late stage of febrile illness, deficiency of Yin and Blood, loss of nourishment of the tongue leading to depression in the tongue. When tongue depression occurs, it is necessary for a professional doctor to analyze the symptoms together with other symptoms and adopt the correct treatment rules and prescriptions to avoid misdiagnosis and adverse effects.