Acyclovir is taken orally. – Treatment of onset Herpes simplex, including Genital Herpes: 200 mg x 5 times/day (usually 4 hours when awake) for about 5-10 days. Patients with serious immunodeficiency or malabsorption patients: 400 mg x 5 times/day for about 5 days. – Prevent Herpes simplex recurrence in patients with normal immunity: 800 mg divided into 2-4 times/day. The dose can be reduced to 400 - 600 mg/day. Can take a higher dose of 1 gram per day. The treatment should be stopped every 6-12 months to re-evaluate. – Prevention of Herpes simplex disease in immunocompoised patients: 200 - 400 mg x 4 times/day. – Treatment to prevent chronic diseases: Not suitable for mild or infrequent recurrence of Herpes simplex infection. In these cases, treatment of each phase of load is more effective, using a dose of 200 mg x 5 times/day for 5 days, preferably in the early stage of symptoms. – The disease of chickenpox: 800 mg x 4 or 5 times/day for about 5-7 days.