Aciclovir is used for the treatment of herpes simplex virus and varicella zoster virus infections, including: Genital herpes simplex, Neonatal herpes simplex, Herpes simplex labialis (cold sores), Shingles, Acute chickenpox in immunocompromised patients, Herpes simplex encephalitis, Acute mucocutaneous HSV infections , Herpes of the eye and herpes simplex blepharitis.