Acyclovir is an antiviral drug used in the treatment of herpes simplex virus infections, herpes zoster, and chickenpox in immunodeficient individuals. Common dosage forms of acyclovir include capsules, tablets, creams and injections. Depending on the dosage form and the disease, the dosage used is different, and patients need to use it under the guidance of a doctor. Take Acyclovir capsules for example. Its instruction manual recommended usage: oral. 1. Genital herpes primary treatment and immunodeficiency skin mucous membrane herpes simplex. For adults, the usual dosage is 0.2 g (1 capsule) 5 times a day for 10 days or 0.4 g (2 capsules) 8 times a day for 5 days; for recurrent infections, 0.2 g (1 capsule) 5 times a day for 5 days. Chronic suppressive therapy for recurrent infections: 0.2 g (1 capsule) 8 times a day for 6 months, increasing the dose to 0.2 g (1 capsule) 5 times a day for 6-12 months if necessary. 2. Herpes zoster: Adults, the usual dose of 0.8 g (4 capsules), 5 times a day for 7-10 days. 3. Varicella: Children over 2 years old should take 20 mg/kg of body weight 4 times a day for 5 days, and start treatment immediately when symptoms appear. 0.8 g (4 capsules) of body weight 4 times a day for 5 days is the usual dosage for children over 40 kg and adults. Dizziness, headache, nausea, vomiting, insomnia and other adverse reactions may occur. This product is contraindicated in people who are allergic to this product. Adult patients with renal insufficiency need to adjust the dose. This product should be used under the guidance of a professional doctor and in accordance with the doctor’s instructions.