Caries will hurt to eat because of caries to a certain depth, the tooth is a layer of hard enamel layer, enamel layer caries down is the dentin layer, dentin wrapped inside the nerve. Nerve is very fragile, once the caries, the closer to the nerve, eating cold, hot, sour, sweet will stimulate the nerve. The most obvious manifestation of the dental nerve is pain, when the patient has a painful sensation will be detected, found that there is a hole in the tooth, only to come to treatment. Only after caries has decayed to a certain degree does it hurt to bite, and most of the time when it hurts to bite is because the food is bitten into the hole, and with pressure it hurts. Sometimes it hurts when you brush your teeth with cold or hot water, when you drink soup, or when you eat popsicles. It also hurts when you eat sour or sweet foods. Since the teeth have decayed to a certain extent by this time, if this happens, patients are advised to go to the hospital as soon as possible.