The difference between Acyclovir Tablets and Famciclovir Tablets is mainly due to the difference in their ingredients as well as the scope of application. 1. Ingredients: The main ingredient of Acyclovir Tablets is Acyclovir, while the main ingredient of Famciclovir Tablets is Famciclovir. 2. Scope of application: Acyclovir tablets are mainly used for the treatment of herpes simplex virus infection, mild herpes zoster in immunocompetent or immunodeficient persons and chickenpox in immunodeficient persons. In addition to herpes zoster or herpes simplex, famciclovir tablets can also be used for some immune deficiency or other viral infections, such as AIDS-induced viral infections with severely impaired immunity, oncology patients receiving chemotherapy, and patients with organ transplants using immunosuppressants. Adverse reactions to acyclovir tablets include dizziness and headache, nausea and vomiting. Adverse reactions to famciclovir tablets are headache, nausea, and are contraindicated in people who are allergic to both drugs. Acyclovir tablets and famciclovir tablets should be consulted with a clinician and taken on medical advice.