Valacyclovir is primarily used in the treatment and management of viral infections caused by herpes viruses. It is effective in treating herpes simplex virus infections, including genital herpes, cold sores, and herpes labialis. Additionally, it is used to manage shingles (herpes zoster) and to prevent the recurrence of these infections in individuals with a history of frequent outbreaks.

In immunocompromised patients, such as those with HIV or undergoing chemotherapy, valacyclovir is often prescribed to prevent or treat herpes-related complications. It can also be used to reduce the risk of transmitting genital herpes to sexual partners when taken as a suppressive therapy.

Furthermore, valacyclovir is sometimes employed in the prevention of cytomegalovirus (CMV) infections in organ transplant recipients. Its ability to inhibit viral replication makes it a valuable tool in controlling and mitigating the impact of these viral infections.