Buy Acivir DT (Acyclovir), Acyclovir is used to viral infections of skin, mucus membrane and genitals caused by herpes simplex virus including shingles. It is also used for treating recurrent herpes simplex infections and to prevent herpes simplex infections in people prone to infections due to a weak immune system (immunocompromised). Acyclovir can also be used to treat chickenpox (also viral infections).