ObjectiveTo investigate the effects of berberine hydrochloride on the expression of urease genes ureA and ureB in Helicobacter pylori （H. pylori） and its biofilm. MethodsThe standard strain 26695 of H. pylori， which was preserved in our laboratory， along with the drug-resistant strains H390， e660， H57， and H389 of H. pylori that were isolated from clinical sources were revived. The minimum inhibitory concentration （MIC） of berberine hydrochloride against the planktonic cells of the aforementioned five strains of H. pylori was determined using the broth dilution method. The combined inhibitory effect of berberine hydrochloride and amoxicillin against the aforementioned four strains of clinically resistant H. pylori was assessed using the checkerboard method. TheMIC of berberine hydrochloride against the biofilms of H. pylori strains 26695 and H390 was determined using the broth dilution method. Planktonic cells and biofilms of the aforementioned H. pylori strains 26695 and H390 were co-incubated with berberine hydrochloride at concentrations of 0.5MIC， MIC， and 2MIC for 2， 8， and 24 hours， respectively. Subsequently， urease activity was measured， and the expression levels of the ureA and ureB genes were detected using RT-qPCR. ResultsBerberine hydrochloride exhibited inhibitory effects against both planktonic cells of the antibiotic-sensitive strain 26695 and the antibiotic-resistant strains H390， e660， H57， and H389 of H. pylori. It also demonstrated inhibitory effects against the biofilms formed by strains 26695 and H390. Furthermore， the combined inhibitory effect of berberine hydrochloride and amoxicillin against antibiotic-resistant strains of H. pylori was either synergistic or additive. Berberine hydrochloride inhibited urease activity in both planktonic cells and biofilms of the H. pylori strains 26695 and H390. Furthermore， berberine hydrochloride downregulated the relative expression levels of the ureA and ureB genes in H. pylori and its biofilms. The relative expression levels of the ureA and ureB genes exhibited a dose- and time-dependent decrease with increasing concentrations of berberine hydrochloride and longer co-incubation times （P<0.05）. ConclusionBerberine hydrochloride inhibits both planktonic cells and biofilms of H. pylori. When combined with amoxicillin， it exerts additive or synergistic effects against H. pylori. Furthermore， by inhibiting urease activity and downregulating the expression of the ureA and ureB genes in H. pylori， berberine hydrochloride contributes to the reduction in growth of both planktonic cells and biofilms.