Herpes simplex virus type 1(HSV-1)is a ubiquitous and widespread human pathogen,which gives rise to a range of diseases,including cold sores,corneal blindness,and encephalitis.Currently,the use of nucleoside analogs,such as acyclovir and penciclovir,in treating HSV-1 infection often presents limi-tation due to their side effects and low efficacy for drug-resistance strains.Therefore,new anti-herpetic drugs and strategies should be urgently developed.Here,we reported that baicalein,a naturally derived compound widely used in Asian countries,strongly inhibited HSV-1 replication in several models.Baica-lein was effective against the replication of both HSV-1/F and HSV-1/Blue(an acyclovir-resistant strain)in vitro.In the ocular inoculation mice model,baicalein markedly reduced in vivo HSV-1/F replication,receded inflammatory storm and attenuated histological changes in the cornea.Consistently,baicalein was found to reduce the mortality of mice,viral loads both in nose and trigeminal ganglia in HSV-1 intra-nasal infection model.Moreover,an ex vivo HSV-1-EGFP infection model established in isolated murine epidermal sheets confirmed that baicalein suppressed HSV-1 replication.Further investigations unraveled that dual mechanisms,inactivating viral particles and inhibiting IκB kinase beta(IKK-β)phosphorylation,were involved in the anti-HSV-1 effect of baicalein.Collectively,our findings identified baicalein as a promising therapy candidate against the infection of HSV-1,especially acyclovir-resistant strain.