Objective: To study the effects of constitutive NOS (cNOS) inhibitor L-nitroarginine on the recovery from traumatic facial paralysis of rats and changes in the expression of CNOS and OX42 in the facial nucleus. Material and Methods: A small dose of L-nitroarginine was intraperitoneally injected into rats around facial paralysis, and the recovery from paralysis was observed at different time points. The immunohistochemical ABC method was used to study changes in cNOS-and OX42-positive neurons in the facial nucleus. Results: Repeated L-nitroarginine treatment could markedly inhibit recovery from traumatic facial paralysis; cNOS immunoreactivity was obviously inhibited in the facial nucleus, while OX42 immunoreactivity clearly increased. Conclusions: Endogenous nitric oxide may play an important mediating role in the recovery from traumatic facial paralysis.