Thick tongue on one side and thin on the other side is considered to be caused by the following reasons: 1, cerebral neuropathy, cerebral neuropathy can occur as a result of facial nerve damage caused by facial paralysis on one side, so that the nerves innervating the tongue will appear corresponding changes, resulting in atrophy of the tongue on one side, thinning, small, for example, cerebral infarction may lead to this effect. 2, local lesions of the tongue, tongue if the corresponding lesions may lead to one side of the tongue becomes thicker, for example, lingual inflammation or edema after the tongue is bitten, it may lead to the above symptoms. For example, tongue inflammation or edema after tongue bite may cause the above symptoms.3. Dietary or allergic factors, long-term use of the lower teeth to chew food or long-term consumption of spicy and allergy-prone food may lead to thickening of one side of the tongue. If the tongue appears to be thin on one side and thick on the other side, you should go to the regular hospital in time to have a relevant examination, and use the correct way of treatment under the guidance of the doctor according to the results of the examination.