Smooth tongue is a condition in which the normal rough surface (papillae) of the tongue shrinks or disappears, making the tongue look bald or shiny and thin. Without this rough surface, the tongue may be tender and sensitive to spicy foods.

This problem can occur because of a lack of folic acid, iron, riboflavin, or vitamin B12 in the diet over a long period of time. With adequate nutrition, symptoms generally begin to improve within 2 weeks, and the tongue may return to normal appearance within a month.

A person with a smooth tongue should avoid irritants, such as spicy foods, alcohol, and smoking or using smokeless (chewing) tobacco. A prescription anesthetic ointment may help relieve the discomfort and tenderness.