Valcivir 1000 tablet contains a class of antiviral medication, valaciclovir, used to fight viral infections. It plays a vital role in treating cold sores (an inflamed blister in or near the mouth caused by infection with the herpes simplex virus), genital herpes (A common sexually transmitted infection marked by genital pain and sores), and herpes zoster (a viral infection that causes a painful rash). Valcivir 1000 tablets do not cure herpes, but rather prevent it from spreading and treat its symptoms.