How long to take Vasiclovir in general needs to be judged according to the cause of the disease, herpes simplex needs to be taken for 7 consecutive days, while herpes zoster needs to be taken for 10 consecutive days. Vasiclovir is mainly used to treat herpes zoster and herpes simplex virus infection. Patients are required to take the drug on an empty stomach before meals for 7 consecutive days for herpes simplex and 10 consecutive days for herpes zoster to ensure the efficacy of the drug. However, it is contraindicated for those who are allergic to the drug, and should be used with caution if the patient is dehydrated, has liver or renal insufficiency, or is allergic to ganciclovir. At the same time, patients need to give the drug as soon as possible after the appearance of herpes symptoms and signs, and patients need to take sufficient water, so as to avoid the precipitation of the drug in the renal tubules. If you are a patient with genital herpes, most of them are susceptible to cervical cancer, so you also need to follow up regularly to detect it as early as possible. Patients are advised to use valaciclovir strictly in accordance with medical advice and to read the instructions before using the drug to understand its precautions and contraindications, etc.