What causes a tongue crack?

General tongue cracks consider physique bias to yin deficiency. Tongue image is the external manifestation of stomach qi and body qi and blood state. Normal tongue image is pale red and moist tongue, thin white and uniform tongue coating. If physique bias to yin deficiency, body fluid deficiency, tongue cracks will appear, and often dry mouth, throat and other conditions, such conditions can be gradually improved by taking some Ziyin food or medicine. Another part is natural tongue image, although the tongue has cracks, but there is no yin deficiency or body fluid deficiency symptoms, can be regarded as normal, do not worry. But whether it is natural tongue image or yin deficiency constitution, life should pay attention to diet, protect spleen and stomach function, ensure the normal metabolism of body fluid.