BACKGROUND Oral lichen planus (OLP) is a chronic inflammatory disease involving the oral mucosa, associated with the T-cell activity that mediates an autoimmune condition, with various predisposing factors, such as herpes simplex virus (HSV). The first-line treatment is topical corticosteroids. However, additional therapy can be given according to the underlying factors. This report assessed the efficacy of oral acyclovir as adjuvant therapy in the management of OLP. CASE REPORT A 73-year-old man came to our unit reporting he had recurring sores on the tongue for the past 10 years. The tongue was painful and there was taste impairment. Intraoral examination showed erosion and erythematous areas surrounded by white net-like plaques on the tongue and buccal mucosa, as well as depapillation on 2/3 dorsal anterior of the tongue. The diagnosis of reticular and erosive OLP was determined based on clinical features. The patient was prescribed topical corticosteroids, multivitamins, and mouthwash containing chlorine dioxide. Supporting examinations were performed to rule out systemic predisposing factors. The patient was referred for anti-HSV-1 IgG testing, and it was reactive (34.8 U/mL). Thus, oral acyclovir was prescribed. After 2 weeks of antiviral treatment, the tongue pain and altered taste were resolved, and the clinical features showed significant improvement. CONCLUSIONS Management of OLP requires a comprehensive approach. OLP symptoms can be relieved if treatment is not only limited to reducing the inflammation but also seeks to remedy other comorbidities, in this case, administration of an antiviral agent to resolve the HSV-1 involvement.