Zovirax 800 Tablet contains Acyclovir 800 mg, an antiviral agent primarily indicated for the treatment of herpes simplex virus infections, including genital herpes, cold sores, and herpes labialis. It is also effective in managing varicella-zoster virus infections such as shingles (herpes zoster) and chickenpox. Acyclovir acts by inhibiting viral DNA synthesis, thereby reducing viral replication and spread within the body. This medication is typically prescribed to reduce the severity and duration of outbreaks and to prevent recurrent episodes in immunocompromised patients. Zovirax 800 Tablet is administered orally, with dosage and duration tailored according to the specific infection and patient condition. Common side effects may include headache, nausea, diarrhea, and abdominal discomfort, which are generally mild and transient. Patients with renal impairment require dosage adjustments to prevent accumulation and toxicity. It is essential to maintain adequate hydration during therapy to minimize the risk of renal adverse effects. Zovirax is contraindicated in patients with known hypersensitivity to acyclovir or valacyclovir. Use during pregnancy and lactation should be under medical supervision, weighing potential benefits against risks. This medication should be stored at room temperature, away from moisture and heat, and kept out of reach of children.