The herpes simplex virus (HSV) is a common virus that can cause sores on the mouth or genitals. There are two main types: HSV-1, which usually leads to cold sores around the mouth, and HSV-2, which typically causes genital herpes. Once a person is infected, the virus remains in the body for life, often lying dormant and reactivating during times of stress or illness. Although there is no cure for herpes, treatments can help manage symptoms and reduce the frequency of outbreaks. It's important to practice safe behaviors, such as using condoms, to lower the risk of spreading the virus to others.