Acyclovir is an antiviral drug that is a synthetic purine nucleoside analog with the chemical name 9-(2-hydroxyethoxymethyl)guanine. There are several formulation types of acyclovir. Acyclovir gel is a white gel formulation of acyclovir that contains more water than cream. Compared to acyclovir cream, the gel is less irritating. The mechanism of action of acyclovir is that after entering the cell, acyclovir mimics the binding of nucleotides to viral polymorphic enzymes, adulterates viral DNA and aborts its extension, thus interfering with viral replication and achieving antiviral effects. It has an inhibitory effect on herpes simplex virus, varicella zoster virus, cytomegalovirus, etc. Acyclovir Gel is indicated for immune compromised patients, non-fatal herpes zoster, herpes simplex virus skin mucosal infections and early genital herpes virus infections. Acyclovir gel is a topical topical drug. In clinical practice, oral acyclovir tablets may be added to the topical application to improve the therapeutic effect. Gloves should be worn during application. Both adults and pediatricians should apply the gel every 3 hours, 6 times a day for 7 days. Adverse reactions such as mild pain, burning, tingling, itching, and rash may be seen.