The purpose of this guidance is to assist sponsors in the development of drugs for the treatment and prevention of recurrent herpes labialis (RHL). Specifically, this guidance addresses the Food and Drug Administration’s (FDA’s) current thinking regarding the overall development program and clinical trial designs to support the development of drug products with an antiviral mechanism of action used to prevent and/or treat RHL caused by either herpes simplex virus type 1 or 2 (HSV-1 or HSV-2) in immunocompetent subjects. This guidance does not address the development of drug products used to treat systemic, genital, or disseminated herpes virus infections or herpes labialis in immunosuppressed subjects.