There are more reasons for astringency of the tongue. If there is a combination of tingling, consider the possibility of insufficient blood circulation, or high blood viscosity or insufficient blood supply to the brain, which requires further examination of blood pressure, blood sugar, blood lipids, and blood viscosity. If there is a combination of bitterness in the tongue, consider the possibility of bile reflux, which leads to bitter symptoms in the mouth. If combined with odor, consider whether there is periodontitis, crown infection, personal hygiene, and smoking. If it is combined with a dry tongue, consider whether it is caused by sleep snoring or insufficient oral hygiene. Therefore, the cause of tongue astringency depends on whether there are other combined symptoms to further determine the specific condition.