A person with herpes gingivostomatitis has an infection caused by Herpes simplex virus type 1. The infection causes painful blisters and ulcers in the mouth, or on the skin around the mouth.

About 4 out 5 adults in the US are infected by the Herpes simplex 1 virus. There is no cure for the infection. After initial infection, the virus causes temporary symptoms that resolve, but additional episodes are common.