Cracks in the tongue are usually caused by a deficiency of stomach yin, which leads to a deficiency in the upper part of the body and causes the tongue to lose moistening. You need to pay attention to your diet and reduce the intake of fatty, sweet and greasy meats, seafood and especially spicy foods, and abstain from alcohol. These foods will consume qi and hurt yin, which will increase the depletion of yin qi and the formation of cracks on the tongue. You need to eat more foods that can nourish yin, such as wolfberry, wuweizi, chasteberry, mulberry, which can nourish the liver and kidneys and can nourish stomach yin. Usually you can also eat Chinese herbal medicine to regulate, such as benefit stomach soup, yu zhu, saxifrage, bing sugar, maitong, these can nourish the qi and benefit the lung, replenish the stomach yin. Comprehensive conditioning, then pay attention to proper exercise and control the diet.