Acyclovir, also known as ACV and acyclovir, has the ability to interfere with viral DNA polymerase and can inhibit the replication of viral DNA. It has activity against herpes simplex virus (HSV), varicella-zoster virus (VZV), EBV, cytomegalovirus, etc. Its main indications are: 1, herpes simplex: clinically used for herpes simplex caused mainly by herpes simplex virus type I and genital herpes caused by herpes simplex virus type II. 2, chickenpox, herpes zoster. 3.Herpes virus caused by meningoencephalitis, hepatitis. 4, oral aphthous ulcers: preventive effect on some severe oral aphthous ulcers. 5.Other: plantar warts, recurrent erythema multiforme, herpetic eczema, lymphoma-like papulosis, hairy mucous membrane leukoplakia. Acyclovir has a low absorption rate but fast onset of action, reaching all tissues in the body and also crossing the blood-brain barrier into the placenta. It is metabolized and excreted by the kidneys in the urine, with no accumulation in the body. It is 160 times more potent than adenosine and 10 times more potent than iodoside in combating herpes virus. However, this drug is alkaline, and mixing with other drugs can easily lead to PH changes, so it should be avoided in combination. Also, it should be used with caution in children, pregnant and lactating women, and newborns should not be configured with a drip solution containing benzyl alcohol dilution, as this can cause a fatal syndrome.