Acyclovir 400 mg is an antiviral medication commonly used to manage and treat infections caused by the herpes virus, including genital herpes, cold sores, and shingles. While it does not cure these viral infections, it helps to reduce the symptoms, prevent outbreaks, and speed up the healing process. Acyclovir works by interfering with the viral replication process, thus controlling the spread of the infection within the body. It?s available in various forms, including oral tablets, and is often prescribed as part of a long-term treatment plan to manage recurrent outbreaks.