Acyclovir cream is a white ointment, the main active ingredient is acyclovir, and the main excipients are petroleum jelly, liquid paraffin, water and preservatives. Acyclovir is an antiviral drug belonging to the purine nucleoside class, capable of inhibiting viral replication and interfering with viral DNA synthesis, especially sensitive to herpes virus and cytomegalovirus. It is mostly used clinically for the treatment of herpetic lesions of the skin and mucous membranes caused by sensitive viral infections, commonly chickenpox, herpes zoster, herpetic pharyngitis, and so on. Usually a small amount of the cream is taken and applied to the affected area.