Thalicfoetine (1), the first O-bridged spirobenzylisoquinoline alkaloid possesses a spiro tetrahydropyridine-furanone core, was isolated from the roots of Thalictrum foetidum. Its structure was elucidated by extensive spectroscopic analyses and ECD calculation. Moreover, 1 exhibited antibacterial activity against Bacillus subtilis significantly with MIC value of 3.12 μg/mL. © 2019 Elsevier Ltd