Numbness and bitterness of the tongue are mostly associated with abnormal liver and gallbladder function or heart fire. First of all, abnormal liver and gallbladder function, liver qi discomfort and bile reflux will mostly cause bitterness in the tongue. If the tongue is red and numb on both sides, but the tongue movement is not affected, it means that the liver is not functioning well and no external evil has invaded the body’s meridians, which is often accompanied by symptoms such as fullness in the chest, breast swelling and pain in the abdomen. If the numbness and bitterness of the tongue is accompanied by sores in the mouth and tongue, insomnia, irritability and other symptoms, it is mostly caused by the heart fire, because the heart opens the tongue, and the numbness and bitterness of the tongue is mostly related to the heart fire burning the oral fluids in the mouth, which does not moisten the tongue, so treatment should be given to clear the heart and defeat the fire.