Valacyclovir is a pro-drug medication used to treat a wide range of viral infections, including cold sores, genital herpes, shingles, and chickenpox. Valacyclovir works by blocking the ability of viruses to replicate in affected cells and tissues. Valacyclovir does this by inhibiting the enzyme known as DNA polymerase, which is responsible for replicating viral genetic material. This helps to reduce symptoms and speed up recovery. Valacyclovir is available in tablet form or an oral suspension and can be taken with food or without. Valacyclovir has been effective at reducing the frequency and severity of future outbreaks of HSV-1 (cold sores), HSV-2 (genital herpes), VZV (shingles), and VZV (chickenpox). Valacyclovir is generally well tolerated with few side effects reported. However, some people may experience nausea, vomiting, headache, or diarrhea when taking valacyclovir. It’s important to follow your doctor’s instructions closely when taking this medication for the best results.