Acyclovir is primarily used to temporarily treat (but not cure) herpes simplex virus. Take Acyclovir at the first sign of herpes related symptoms, such as: tingling, blisters or a burning sensation. Acyclovir reduces the occurrence of outbreaks associated with herpes, genital warts, cold sores, chickenpox, and shingles (herpes zoster). This treatment works to destroy much of the herpes virus, diminishing it's the growth and the potential to spread.