Natclovir 250 mg Capsules are recommended for eye infections caused by Herpes simplex virus. An antiviral drug, this medicine prevents the multiplication of the virus in human cells. This action of the medicine stops the virus from producing new viruses. Prescribed for cytomegalovirus (CMV) retinitis, this medicine is useful for patients undergoing transplant for prevention of CMV retinitis and cytomegalovirus infections. It contains Ganciclovir as an active ingredient and works by blocking the viral DNA replication.