The difference between vasiclovir and famciclovir lies in the differences in drug composition, therapeutic scope and contraindications, etc. It is recommended that patients take medication under the guidance of a doctor. 1. Composition: The main ingredient of vasiclovir is vasiclovir; the main ingredient of famciclovir is famciclovir. 2. Therapeutic range: Valaciclovir can be used to treat herpes zoster, herpes simplex virus, and primary or recurrent genital herpes virus infections; while famciclovir is suitable for herpes zoster and primary genital herpes. 3. Contraindications: The contraindications of valaciclovir are allergy to any of the components of valaciclovir and acyclovir, while the contraindications of famciclovir are allergy to any of the components of famciclovir and penciclovir. When patients with adverse reactions to the use of valaciclovir or famciclovir, it is recommended that they go to a regular hospital in time for examination and symptomatic treatment under the guidance of a professional doctor.