Aciclovir (Xyclovirax) 200mg Antiviral Tablets 100's are oral antiviral medications used to treat infections caused by the herpes simplex virus (such as cold sores, genital herpes), as well as to manage varicella-zoster virus (chickenpox and shingles). Each tablet contains 200mg of aciclovir, which works by inhibiting the replication of the virus, reducing the severity and duration of the infection. The pack contains 100 tablets, which are typically taken as prescribed by a healthcare provider.