Fluorouracil Cream Is Not a Treatment for Cold Sores

Fluorouracil (5-FU) cream is a topical chemotherapeutic agent used for actinic keratoses and superficial basal cell carcinomas. It has no antiviral activity and is ineffective against herpes simplex virus (HSV-1), the cause of cold sores. Cold sores require antiviral medications (e.g., acyclovir, valacyclovir).