Introduction: Neuregulin-1 (NRG-1) appears to play a role in the pathogenesis of several neuropsychiatric disorders, including epilepsy. We conducted a study to investigate the effect of anti-seizure medication on NRG-1 mRNA and NRG-1 protein levels in patients with first-episode focal epilepsy. Methods: The levels of NRG-1 mRNA isoforms (type I, II, III, and IV) in peripheral blood mononuclear cells (PBMCs) of 39 healthy controls, 39 first-episode focal epilepsy patients before anti-seizure medication (ASM) therapy and four weeks after administration of ASM were measured by RT-qPCR, and the levels of NRG-1 protein in the serum of samples of each group were determined using ELISA. In addition the relationship between efficacy, NRG-1 mRNA expression, and NRG-1 protein expression was analyzed. Results: The levels of NRG-1 mRNA progressively increased in patients with first-episode focal epilepsy treated with ASM and were distinctly different from those before medication, but remained lower than in healthy controls (all P < 0.001). Before and after drug administration, NRG-1 protein levels were substantially higher in epileptic patients than in healthy controls, and no significant changes were detected with prolonged follow-up (P < 0.001). Patients with epilepsy who utilized ASM were able to control seizures with an overall efficacy of 97.4%. There was a negative correlation between NRG-1 mRNA levels and efficacy: as NRG-1 mRNA levels increased, seizures reduced (all P < 0.05). Conclusion: Our research indicated that NRG-1 may play a role in the pathophysiology of epilepsy. NRG-1 mRNA may provide ideas for the discovery of novel epilepsy therapeutic markers and therapeutic targets for novel ASM.